$ICLR
ICON PLC Stock $iclr

$iclr Overview Financials Valuation SEC Filings Company Website

2022 Q4 Form 20-F Financial Statement

#000106095523000007 Filed on February 24, 2023

Income Statement

Concept	2022 Q4	2022	2021 Q4
Revenue	$1.962B	$7.741B	$1.885B
YoY Change	4.08%	41.24%	147.98%
Cost Of Revenue	$1.378B	$5.527B	$1.357B
YoY Change	1.61%	39.21%	153.69%
Gross Profit	$583.7M	$2.214B	$528.6M
YoY Change	10.42%	46.59%	134.42%
Gross Profit Margin	29.75%	28.6%	28.04%
Selling, General & Admin	$229.2M	$778.8M	$203.5M
YoY Change	12.6%	32.5%	129.96%
% of Gross Profit	39.26%	35.17%	38.5%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$142.2M	$569.5M	$139.7M
YoY Change	1.83%	80.81%	716.78%
% of Gross Profit	24.37%	25.72%	26.42%
Operating Expenses	$371.4M	$778.8M	$343.2M
YoY Change	8.22%	-13.73%	224.68%
Operating Profit	$212.3M	$795.2M	$185.4M
YoY Change	14.51%	30.82%	54.78%
Interest Expense	-$74.57M	$229.7M	-$52.76M
YoY Change	41.33%	-226.33%	1548.78%
% of Operating Profit	-35.12%	28.89%	-28.45%
Other Income/Expense, Net
YoY Change
Pretax Income	$128.8M	$567.9M	$91.77M
YoY Change	40.34%	188.72%	-21.36%
Income Tax	$10.86M	$59.41M	$14.62M
% Of Pretax Income	8.43%	10.46%	15.93%
Net Earnings	$117.4M	$505.3M	$76.47M
YoY Change	53.59%	229.87%	-24.44%
Net Earnings / Revenue	5.99%	6.53%	4.06%
Basic Earnings Per Share		$6.20
Diluted Earnings Per Share	$1.42	$6.13	$921.5K
COMMON SHARES
Basic Shares Outstanding	81.72M shares	81.53M shares
Diluted Shares Outstanding		82.47M shares

Balance Sheet

Concept	2022 Q4	2022	2021 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments	$290.5M	$290.5M	$753.9M
YoY Change	-61.47%	-61.47%	-10.46%
Cash & Equivalents	$288.8M	$288.8M	$752.2M
Short-Term Investments	$1.700M	$1.713M	$1.712M
Other Short-Term Assets	$137.1M	$137.1M	$114.3M
YoY Change	19.92%	19.92%	113.69%
Inventory
Prepaid Expenses
Receivables	$1.731B	$2.689B	$1.966B
Other Receivables	$112.4M	$112.4M	$107.1M
Total Short-Term Assets	$3.229B	$3.229B	$2.941B
YoY Change	9.79%	9.79%	39.86%
LONG-TERM ASSETS
Property, Plant & Equipment	$350.3M	$504.2M	$534.6M
YoY Change	-34.47%	-5.69%	106.48%
Goodwill	$8.972B		$9.038B
YoY Change	-0.73%		865.33%
Intangibles
YoY Change
Long-Term Investments	$0.00	$32.63M	$24.97M
YoY Change	-100.0%	30.71%	22.98%
Other Assets	$70.79M	$147.7M	$118.9M
YoY Change	-40.49%	24.19%	255.07%
Total Long-Term Assets	$13.96B	$13.96B	$14.45B
YoY Change	-3.39%	-3.39%	984.04%
TOTAL ASSETS
Total Short-Term Assets	$3.229B	$3.229B	$2.941B
Total Long-Term Assets	$13.96B	$13.96B	$14.45B
Total Assets	$17.19B	$17.19B	$17.39B
YoY Change	-1.16%	-1.16%	406.09%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$81.19M	$81.19M	$90.76M
YoY Change	-10.54%	-10.54%	77.62%
Accrued Expenses	$43.66M	$439.5M	$49.95M
YoY Change	-12.6%	-5.1%	105.55%
Deferred Revenue	$1.507B		$1.324B
YoY Change	13.86%
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$55.15M	$55.15M	$55.15M
YoY Change	0.0%	0.0%
Total Short-Term Liabilities	$2.691B	$2.691B	$2.479B
YoY Change	8.54%	8.54%	120.57%
LONG-TERM LIABILITIES
Long-Term Debt	$4.599B	$4.599B	$5.381B
YoY Change	-14.53%	-14.53%	1444.09%
Other Long-Term Liabilities	$38.26M	$409.1M	$374.2M
YoY Change	-89.78%	9.33%	265.06%
Total Long-Term Liabilities	$4.637B	$5.008B	$5.755B
YoY Change	-19.43%	-12.98%	1176.13%
TOTAL LIABILITIES
Total Short-Term Liabilities	$2.691B	$2.691B	$2.479B
Total Long-Term Liabilities	$4.637B	$5.008B	$5.755B
Total Liabilities	$8.687B	$8.687B	$9.320B
YoY Change	-6.79%	-6.79%	487.88%
SHAREHOLDERS EQUITY
Retained Earnings	$1.821B		$1.416B
YoY Change	28.62%
Common Stock	$6.847B		$6.741B
YoY Change	1.58%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$8.498B	$8.498B	$8.067B
YoY Change
Total Liabilities & Shareholders Equity	$17.19B	$17.19B	$17.39B
YoY Change	-1.16%	-1.16%	406.09%

Cashflow Statement

Concept	2022 Q4	2022	2021 Q4
OPERATING ACTIVITIES
Net Income	$117.4M	$505.3M	$76.47M
YoY Change	53.59%	229.87%	-24.44%
Depreciation, Depletion And Amortization	$142.2M	$569.5M	$139.7M
YoY Change	1.83%	80.81%	716.78%
Cash From Operating Activities	-$59.43M	$563.3M	$289.8M
YoY Change	-120.5%	-32.06%	48.32%
INVESTING ACTIVITIES
Capital Expenditures	$57.02M	$142.2M	-$47.68M
YoY Change	-219.57%	-251.64%	106.42%
Acquisitions
YoY Change
Other Investing Activities	-$1.867M	-$3.707M	-$11.33M
YoY Change	-83.53%	-99.94%	2166.8%
Cash From Investing Activities	-$58.88M	-$145.9M	-$59.02M
YoY Change	-0.23%	-97.58%	151.14%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$99.98M	$14.52M
YoY Change		-15.69%	1513.22%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-193.1M	-$864.2M	-485.5M
YoY Change	-60.22%	-116.9%	966.96%
NET CHANGE
Cash From Operating Activities	-59.43M	$563.3M	289.8M
Cash From Investing Activities	-58.88M	-$145.9M	-59.02M
Cash From Financing Activities	-193.1M	-$864.2M	-485.5M
Net Change In Cash	-311.4M	-$463.4M	-254.7M
YoY Change	22.3%	476.68%	-301.47%
FREE CASH FLOW
Cash From Operating Activities	-$59.43M	$563.3M	$289.8M
Capital Expenditures	$57.02M	$142.2M	-$47.68M
Free Cash Flow	-$116.4M	$421.2M	$337.5M
YoY Change	-134.5%	-54.37%	54.46%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2022	dei	Amendment Flag AmendmentFlag	false
CY2022	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2022
CY2022	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2022	dei	Entity Central Index Key EntityCentralIndexKey	0001060955
CY2022Q4	us-gaap	Operating Lease Liability Current Statement Of Financial Position Extensible List OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2022#OtherLiabilitiesCurrent
CY2021Q4	us-gaap	Operating Lease Liability Current Statement Of Financial Position Extensible List OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2022#OtherLiabilitiesCurrent
CY2022	dei	Document Type DocumentType	20-F
CY2022	dei	Document Registration Statement DocumentRegistrationStatement	false
CY2022	dei	Document Annual Report DocumentAnnualReport	true
CY2022	dei	Document Period End Date DocumentPeriodEndDate	2022-12-31
CY2022	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2022	dei	Document Transition Report DocumentTransitionReport	false
CY2022	dei	Document Shell Company Report DocumentShellCompanyReport	false
CY2022	dei	Entity File Number EntityFileNumber	333-08704
CY2022	dei	Entity Registrant Name EntityRegistrantName	ICON PLC
CY2022	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	L2
CY2022	dei	Entity Address Address Line1 EntityAddressAddressLine1	South County Business Park,
CY2022	dei	Entity Address Address Line2 EntityAddressAddressLine2	Leopardstown,
CY2022	dei	Entity Address City Or Town EntityAddressCityOrTown	Dublin 18, D18 X5R3
CY2022	dei	Entity Address Country EntityAddressCountry	IE
CY2022	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	D18 X5R3
CY2022	dei	Security12b Title Security12bTitle	ORDINARY SHARES, PAR VALUE €0.06 EACH
CY2022	dei	Trading Symbol TradingSymbol	ICLR
CY2022	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2022Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	81723555	shares
CY2022	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2022	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2022	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2022	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2022	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2022	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2022	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2022	dei	Document Accounting Standard DocumentAccountingStandard	U.S. GAAP
CY2022	dei	Entity Shell Company EntityShellCompany	false
CY2022	dei	Auditor Firm AuditorFirmId	1116
CY2022	dei	Auditor Name AuditorName	KPMG
CY2022	dei	Auditor Location AuditorLocation	Dublin, Ireland
CY2022Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	288768000	usd
CY2021Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	752213000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	1713000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	1712000	usd
CY2022Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	1731388000	usd
CY2021Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	1342770000	usd
CY2022Q4	us-gaap	Contract With Customer Asset Gross Current ContractWithCustomerAssetGrossCurrent	957655000	usd
CY2021Q4	us-gaap	Contract With Customer Asset Gross Current ContractWithCustomerAssetGrossCurrent	623121000	usd
CY2022Q4	us-gaap	Nontrade Receivables Current NontradeReceivablesCurrent	63658000	usd
CY2021Q4	us-gaap	Nontrade Receivables Current NontradeReceivablesCurrent	56760000	usd
CY2022Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	137094000	usd
CY2021Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	114323000	usd
CY2022Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	48790000	usd
CY2021Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	50299000	usd
CY2022Q4	us-gaap	Assets Current AssetsCurrent	3229066000	usd
CY2021Q4	us-gaap	Assets Current AssetsCurrent	2941198000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	350320000	usd
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	336444000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	8971670000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	9037931000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	4278659000	usd
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	4710843000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	153832000	usd
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	198123000	usd
CY2022Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	70790000	usd
CY2021Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	70557000	usd
CY2022Q4	us-gaap	Income Taxes Receivable Noncurrent IncomeTaxesReceivableNoncurrent	21380000	usd
CY2021Q4	us-gaap	Income Taxes Receivable Noncurrent IncomeTaxesReceivableNoncurrent	18637000	usd
CY2022Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	76930000	usd
CY2021Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	48392000	usd
CY2022Q4	us-gaap	Equity Method Investments EquityMethodInvestments	0	usd
CY2021Q4	us-gaap	Equity Method Investments EquityMethodInvestments	2373000	usd
CY2022Q4	us-gaap	Other Long Term Investments OtherLongTermInvestments	32631000	usd
CY2021Q4	us-gaap	Other Long Term Investments OtherLongTermInvestments	22592000	usd
CY2022Q4	us-gaap	Assets Assets	17185278000	usd
CY2021Q4	us-gaap	Assets Assets	17387090000	usd
CY2022Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	81194000	usd
CY2021Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	90764000	usd
CY2022Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	1507449000	usd
CY2021Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	1323961000	usd
CY2022Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	1005025000	usd
CY2021Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	949629000	usd
CY2022Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	41783000	usd
CY2021Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	59433000	usd
CY2022Q4	us-gaap	Lines Of Credit Current LinesOfCreditCurrent	55150000	usd
CY2021Q4	us-gaap	Lines Of Credit Current LinesOfCreditCurrent	55150000	usd
CY2022Q4	us-gaap	Liabilities Current LiabilitiesCurrent	2690601000	usd
CY2021Q4	us-gaap	Liabilities Current LiabilitiesCurrent	2478937000	usd
CY2022Q4	us-gaap	Long Term Line Of Credit LongTermLineOfCredit	4599037000	usd
CY2021Q4	us-gaap	Long Term Line Of Credit LongTermLineOfCredit	5381162000	usd
CY2022Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	131644000	usd
CY2021Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	159483000	usd
CY2022Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	38260000	usd
CY2021Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	42596000	usd
CY2022Q4	us-gaap	Accrued Income Taxes Noncurrent AccruedIncomeTaxesNoncurrent	239188000	usd
CY2021Q4	us-gaap	Accrued Income Taxes Noncurrent AccruedIncomeTaxesNoncurrent	172109000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	988585000	usd
CY2021Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	1085976000	usd
CY2022Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies	0	usd
CY2021Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies	0	usd
CY2022Q4	us-gaap	Liabilities Liabilities	8687315000	usd
CY2021Q4	us-gaap	Liabilities Liabilities	9320263000	usd
CY2022Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	6
CY2021Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	6
CY2022Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2021Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2022Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	81723555	shares
CY2022Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	81723555	shares
CY2021Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	81554683	shares
CY2021Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	81554683	shares
CY2022Q4	us-gaap	Common Stock Value CommonStockValue	6649000	usd
CY2021Q4	us-gaap	Common Stock Value CommonStockValue	6640000	usd
CY2022Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	6840306000	usd
CY2021Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	6733910000	usd
CY2022Q4	iclr	Other Undenominated Capital OtherUndenominatedCapital	1162000	usd
CY2021Q4	iclr	Other Undenominated Capital OtherUndenominatedCapital	1134000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-171538000	usd
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-90937000	usd
CY2022Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1821384000	usd
CY2021Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1416080000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	8497963000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	8066827000	usd
CY2022Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	17185278000	usd
CY2021Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	17387090000	usd
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	7741386000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	5480826000	usd
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2797288000	usd
CY2022	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	5527045000	usd
CY2021	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	3972612000	usd
CY2020	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	1979883000	usd
CY2022	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	778753000	usd
CY2021	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	585330000	usd
CY2020	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	342449000	usd
CY2022	us-gaap	Depreciation And Amortization DepreciationAndAmortization	569513000	usd
CY2021	us-gaap	Depreciation And Amortization DepreciationAndAmortization	314987000	usd
CY2020	us-gaap	Depreciation And Amortization DepreciationAndAmortization	66126000	usd
CY2022	iclr	Business Combination Integration Related Costs Credits BusinessCombinationIntegrationRelatedCostsCredits	39695000	usd
CY2021	iclr	Business Combination Integration Related Costs Credits BusinessCombinationIntegrationRelatedCostsCredits	198263000	usd
CY2020	iclr	Business Combination Integration Related Costs Credits BusinessCombinationIntegrationRelatedCostsCredits	-759000	usd
CY2022	us-gaap	Restructuring Costs RestructuringCosts	31143000	usd
CY2021	us-gaap	Restructuring Costs RestructuringCosts	31105000	usd
CY2020	us-gaap	Restructuring Costs RestructuringCosts	18089000	usd
CY2022	us-gaap	Costs And Expenses CostsAndExpenses	6946149000	usd
CY2021	us-gaap	Costs And Expenses CostsAndExpenses	5102297000	usd
CY2020	us-gaap	Costs And Expenses CostsAndExpenses	2405788000	usd
CY2022	us-gaap	Operating Income Loss OperatingIncomeLoss	795237000	usd
CY2021	us-gaap	Operating Income Loss OperatingIncomeLoss	378529000	usd
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	391500000	usd
CY2022	us-gaap	Investment Income Interest InvestmentIncomeInterest	2345000	usd
CY2021	us-gaap	Investment Income Interest InvestmentIncomeInterest	574000	usd
CY2020	us-gaap	Investment Income Interest InvestmentIncomeInterest	2724000	usd
CY2022	us-gaap	Interest Expense InterestExpense	229731000	usd
CY2021	us-gaap	Interest Expense InterestExpense	182423000	usd
CY2020	us-gaap	Interest Expense InterestExpense	13019000	usd
CY2022	us-gaap	Income Loss Including Portion Attributable To Noncontrolling Interest IncomeLossIncludingPortionAttributableToNoncontrollingInterest	567851000	usd
CY2021	us-gaap	Income Loss Including Portion Attributable To Noncontrolling Interest IncomeLossIncludingPortionAttributableToNoncontrollingInterest	196680000	usd
CY2020	us-gaap	Income Loss Including Portion Attributable To Noncontrolling Interest IncomeLossIncludingPortionAttributableToNoncontrollingInterest	381205000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	59411000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	41334000	usd
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	47875000	usd
CY2022	iclr	Income Loss From Continuing Operations Before Equity Method Investments Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNoncontrollingInterest	508440000	usd
CY2021	iclr	Income Loss From Continuing Operations Before Equity Method Investments Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNoncontrollingInterest	155346000	usd
CY2020	iclr	Income Loss From Continuing Operations Before Equity Method Investments Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsNoncontrollingInterest	333330000	usd
CY2022	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-3136000	usd
CY2021	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-2161000	usd
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-366000	usd
CY2022	us-gaap	Profit Loss ProfitLoss	505304000	usd
CY2021	us-gaap	Profit Loss ProfitLoss	153185000	usd
CY2020	us-gaap	Profit Loss ProfitLoss	332964000	usd
CY2022	us-gaap	Net Income Loss Attributable To Redeemable Noncontrolling Interest NetIncomeLossAttributableToRedeemableNoncontrollingInterest	0	usd
CY2021	us-gaap	Net Income Loss Attributable To Redeemable Noncontrolling Interest NetIncomeLossAttributableToRedeemableNoncontrollingInterest	0	usd
CY2020	us-gaap	Net Income Loss Attributable To Redeemable Noncontrolling Interest NetIncomeLossAttributableToRedeemableNoncontrollingInterest	633000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	505304000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	153185000	usd
CY2020	us-gaap	Net Income Loss NetIncomeLoss	332331000	usd
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.20
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.28
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.20
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.13
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.25
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.15
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	81532320	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	67110186	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	52859911	shares
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	-113000	usd
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	82468363	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	68068311	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53283585	shares
CY2022	us-gaap	Profit Loss ProfitLoss	505304000	usd
CY2021	us-gaap	Profit Loss ProfitLoss	153185000	usd
CY2020	us-gaap	Profit Loss ProfitLoss	332964000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-89530000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-60617000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	46526000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	0	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	0	usd
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-231000	usd
CY2022	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	12657000	usd
CY2021	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	4266000	usd
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-4138000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	0	usd
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	910000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-3728000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	778000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-905000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	424703000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	97725000	usd
CY2020	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	373306000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	0	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	0	usd
CY2020	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	633000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	424703000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	97725000	usd
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	372673000	usd
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	1618055000	usd
CY2020	us-gaap	Net Income Loss NetIncomeLoss	332331000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	46526000	usd
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-231000	usd
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-4138000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	910000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-905000	usd
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	372673000	usd
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	13189000	usd
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	14000	usd
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	25981000	usd
CY2020	us-gaap	Adjustments To Additional Paid In Capital Stock Issued Issuance Costs AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	14000	usd
CY2020	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	175000000	usd
CY2020	iclr	Adjustment To Retained Earning Share Repurchase Costs AdjustmentToRetainedEarningShareRepurchaseCosts	140000	usd
CY2020	iclr	Redeemable Noncontrolling Interest Increase From Business Combination RedeemableNoncontrollingInterestIncreaseFromBusinessCombination	-4522000	usd
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	1850236000	usd
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	1850236000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	153185000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-60617000	usd
CY2021	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	4266000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	-113000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	778000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	97725000	usd
CY2021	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	118589000	usd
CY2021	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	23000	usd
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	133553000	usd
CY2021	us-gaap	Adjustments To Additional Paid In Capital Stock Issued Issuance Costs AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	853000	usd
CY2021	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	5658155000	usd
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Other Longterm Incentive Plans Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationOtherLongtermIncentivePlansRequisiteServicePeriodRecognition	209399000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	8066827000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	8066827000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	505304000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-89530000	usd
CY2022	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	12657000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-3728000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	424703000	usd
CY2022	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	35828000	usd
CY2022	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	16000	usd
CY2022	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	70606000	usd
CY2022	us-gaap	Adjustments To Additional Paid In Capital Stock Issued Issuance Costs AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	17000	usd
CY2022	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	99983000	usd
CY2022	iclr	Adjustment To Retained Earning Share Repurchase Costs AdjustmentToRetainedEarningShareRepurchaseCosts	17000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	8497963000	usd
CY2022	us-gaap	Profit Loss ProfitLoss	505304000	usd
CY2021	us-gaap	Profit Loss ProfitLoss	153185000	usd
CY2020	us-gaap	Profit Loss ProfitLoss	332964000	usd
CY2022	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	569513000	usd
CY2021	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	314987000	usd
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	66126000	usd
CY2022	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	28767000	usd
CY2021	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	20037000	usd
CY2020	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	5411000	usd
CY2022	us-gaap	Operating Lease Right Of Use Asset Amortization Expense OperatingLeaseRightOfUseAssetAmortizationExpense	45215000	usd
CY2021	us-gaap	Operating Lease Right Of Use Asset Amortization Expense OperatingLeaseRightOfUseAssetAmortizationExpense	45339000	usd
CY2020	us-gaap	Operating Lease Right Of Use Asset Amortization Expense OperatingLeaseRightOfUseAssetAmortizationExpense	28480000	usd
CY2022	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-3136000	usd
CY2021	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-2161000	usd
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-366000	usd
CY2022	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	17749000	usd
CY2021	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	12890000	usd
CY2020	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	523000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	70523000	usd
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	133844000	usd
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	26271000	usd
CY2022	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	usd
CY2021	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-14434000	usd
CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	usd
CY2022	iclr	Gain Loss On Issuance Of Debt GainLossOnIssuanceOfDebt	0	usd
CY2021	iclr	Gain Loss On Issuance Of Debt GainLossOnIssuanceOfDebt	-59460000	usd
CY2020	iclr	Gain Loss On Issuance Of Debt GainLossOnIssuanceOfDebt	0	usd
CY2022	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-124985000	usd
CY2021	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-60616000	usd
CY2020	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	927000	usd
CY2022	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	13009000	usd
CY2021	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	6054000	usd
CY2020	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	-5979000	usd
CY2022	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-11324000	usd
CY2021	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-4480000	usd
CY2020	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	7859000	usd
CY2022	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	420695000	usd
CY2021	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-113513000	usd
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	175040000	usd
CY2022	us-gaap	Increase Decrease In Contract With Customer Asset IncreaseDecreaseInContractWithCustomerAsset	332592000	usd
CY2021	us-gaap	Increase Decrease In Contract With Customer Asset IncreaseDecreaseInContractWithCustomerAsset	17656000	usd
CY2020	us-gaap	Increase Decrease In Contract With Customer Asset IncreaseDecreaseInContractWithCustomerAsset	5748000	usd
CY2022	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	192944000	usd
CY2021	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	-69121000	usd
CY2020	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	291844000	usd
CY2022	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	10121000	usd
CY2021	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	108259000	usd
CY2020	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	-2209000	usd
CY2022	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	563315000	usd
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	829142000	usd
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	568035000	usd
CY2022	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	142160000	usd
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	93750000	usd
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	40885000	usd
CY2022	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	0	usd
CY2021	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	5914475000	usd
CY2020	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	47931000	usd
CY2022	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	0	usd
CY2021	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	2450000	usd
CY2020	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	2450000	usd
CY2022	us-gaap	Payments To Fund Longterm Loans To Related Parties PaymentsToFundLongtermLoansToRelatedParties	0	usd
CY2021	us-gaap	Payments To Fund Longterm Loans To Related Parties PaymentsToFundLongtermLoansToRelatedParties	10000000	usd
CY2020	us-gaap	Payments To Fund Longterm Loans To Related Parties PaymentsToFundLongtermLoansToRelatedParties	0	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	481000	usd
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	497000	usd
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	47902000	usd
CY2022	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	482000	usd
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	480000	usd
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	0	usd
CY2022	us-gaap	Proceeds From Sale Of Longterm Investments ProceedsFromSaleOfLongtermInvestments	1906000	usd
CY2021	us-gaap	Proceeds From Sale Of Longterm Investments ProceedsFromSaleOfLongtermInvestments	500000	usd
CY2020	us-gaap	Proceeds From Sale Of Longterm Investments ProceedsFromSaleOfLongtermInvestments	87000	usd
CY2022	us-gaap	Payments To Acquire Longterm Investments PaymentsToAcquireLongtermInvestments	5612000	usd
CY2021	us-gaap	Payments To Acquire Longterm Investments PaymentsToAcquireLongtermInvestments	4077000	usd
CY2020	us-gaap	Payments To Acquire Longterm Investments PaymentsToAcquireLongtermInvestments	3299000	usd
CY2022	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-145867000	usd
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-6024235000	usd
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-46576000	usd
CY2022	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	0	usd
CY2021	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	30328000	usd
CY2020	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	1554000	usd
CY2022	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	75000000	usd
CY2021	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	5905100000	usd
CY2020	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	350000000	usd
CY2022	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	875000000	usd
CY2021	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	877780000	usd
CY2020	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	350000000	usd
CY2022	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	0	usd
CY2021	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	0	usd
CY2020	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	43923000	usd
CY2022	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	35844000	usd
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	118589000	usd
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	13203000	usd
CY2022	us-gaap	Payments Of Stock Issuance Costs PaymentsOfStockIssuanceCosts	17000	usd
CY2021	us-gaap	Payments Of Stock Issuance Costs PaymentsOfStockIssuanceCosts	853000	usd
CY2020	us-gaap	Payments Of Stock Issuance Costs PaymentsOfStockIssuanceCosts	14000	usd
CY2022	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	99983000	usd
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	usd
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	175000000	usd
CY2022	iclr	Payments For Share Repurchase Costs PaymentsForShareRepurchaseCosts	17000	usd
CY2021	iclr	Payments For Share Repurchase Costs PaymentsForShareRepurchaseCosts	0	usd
CY2020	iclr	Payments For Share Repurchase Costs PaymentsForShareRepurchaseCosts	140000	usd
CY2022	us-gaap	Payments For Hedge Financing Activities PaymentsForHedgeFinancingActivities	0	usd
CY2021	us-gaap	Payments For Hedge Financing Activities PaymentsForHedgeFinancingActivities	0	usd
CY2020	us-gaap	Payments For Hedge Financing Activities PaymentsForHedgeFinancingActivities	905000	usd
CY2022	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-864173000	usd
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	5114728000	usd
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-208333000	usd
CY2022	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-16720000	usd
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-7727000	usd
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	6870000	usd
CY2022	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-463445000	usd
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-88092000	usd
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	319996000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	752213000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	840305000	usd
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	520309000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	288768000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	752213000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	840305000	usd
CY2022	us-gaap	Nature Of Operations NatureOfOperations	Description of Business <div style="text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:120%">ICON plc and its subsidiaries ("the Company" or "ICON") is a clinical research organization ("CRO"), providing outsourced development services on a global basis to the pharmaceutical, biotechnology and medical device industries. We specialize in the strategic development, management and analysis of programs that support all stages of the clinical development process from compound selection to Phase I-IV clinical studies. Our mission is to improve the lives of patients by accelerating the development of our customers' drugs and devices through innovative solutions.</span></div><div><span><br/></span></div><div style="text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:120%">We believe that we are one of a select group of CROs with the expertise and capability to conduct clinical trials in most major therapeutic areas on a global basis and have the operational flexibility to provide development services on a stand-alone basis or as part of an integrated "full-service" solution. At December 31, 2022 we had approximately 41,100 employees, in 111 locations in 53 countries. During the year ended December 31, 2022, we derived approximately 46.2%, 46.5% and 7.3% of our revenue in the United States, Europe and Rest of World, respectively.</span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:120%">ICON’s ordinary shares are traded on the NASDAQ Global Select Market under the symbol “ICLR”.</span></div><div><span><br/></span></div><div style="text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:120%">We began operations in 1990 and have expanded our business through internal growth, together with a number of strategic acquisitions to enhance our capabilities and expertise in certain areas of the clinical development process. We are incorporated in Ireland and our principal executive office is located at: South County Business Park, Leopardstown, Dublin 18, Republic of Ireland. The contact telephone number of this office is +353 1 2912000.</span></div>
CY2022Q4	dei	Entity Number Of Employees EntityNumberOfEmployees	41100	employee
CY2022Q4	iclr	Number Of Locations NumberOfLocations	111	location
CY2022Q4	us-gaap	Number Of Countries In Which Entity Operates NumberOfCountriesInWhichEntityOperates	53	country
CY2022	us-gaap	Use Of Estimates UseOfEstimates	<div style="text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-style:italic;font-weight:700;line-height:120%">Use of estimates</span></div><div><span><br/></span></div><div style="text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:120%">The preparation of financial statements in conformity with generally accepted accounting principles in the United States requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reported period. Actual results could differ from those estimates. The principal management estimates and judgments used in preparing the financial statements relate to revenue recognition and intangible assets acquired in a business combination.</span></div>
CY2020	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-5979000	usd
CY2022	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	25997000	usd
CY2021	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	14316000	usd
CY2022	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-style:italic;font-weight:700;line-height:120%">Reclassifications</span></div><div style="margin-bottom:9pt;margin-top:6pt;text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9pt;font-weight:400;line-height:120%">Certain prior period amounts in the consolidated financial statements and accompanying notes have been reclassified to conform to the current period’s presentation. Most notably, the Company has presented transaction and integration-related expenses as a separate line in the Consolidated Statement of Operations and reclassified certain costs incurred in the year ended December 31, 2020 within this line. These costs consist of transaction and integration-related expenses and contingent consideration valuation adjustments related to ICON's prior period acquisitions. These costs were previously presented in the selling, general and administrative expenses but have been reclassified to transaction and integration-related expenses to conform to the current period’s presentation.</span></div>
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	7741386000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	5480826000	usd
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2797288000	usd
CY2022Q4	us-gaap	Billed Contract Receivables BilledContractReceivables	1751950000	usd
CY2021Q4	us-gaap	Billed Contract Receivables BilledContractReceivables	1349851000	usd
CY2022Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	20562000	usd
CY2021Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	7081000	usd
CY2022Q4	iclr	Contracts Receivable Gross ContractsReceivableGross	1731388000	usd
CY2021Q4	iclr	Contracts Receivable Gross ContractsReceivableGross	1342770000	usd
CY2022Q4	us-gaap	Contract With Customer Asset Gross Current ContractWithCustomerAssetGrossCurrent	957655000	usd
CY2021Q4	us-gaap	Contract With Customer Asset Gross Current ContractWithCustomerAssetGrossCurrent	623121000	usd
CY2022Q4	iclr	Contracts Receivable Net ContractsReceivableNet	2689043000	usd
CY2021Q4	iclr	Contracts Receivable Net ContractsReceivableNet	1965891000	usd
CY2022Q4	us-gaap	Contract With Customer Asset Gross Current ContractWithCustomerAssetGrossCurrent	957655000	usd
CY2021Q4	us-gaap	Contract With Customer Asset Gross Current ContractWithCustomerAssetGrossCurrent	623121000	usd
CY2022	iclr	Increase Decrease In Contractwith Customer Asset Gross Current IncreaseDecreaseInContractwithCustomerAssetGrossCurrent	334534000	usd
CY2022	iclr	Increase Decrease In Contractwith Customer Asset Gross Current Percent IncreaseDecreaseInContractwithCustomerAssetGrossCurrentPercent	0.537
CY2022Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	1507449000	usd
CY2021Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	1323961000	usd
CY2022	iclr	Increase Decrease In Contracts With Customers Liability Current IncreaseDecreaseInContractsWithCustomersLiabilityCurrent	183488000	usd
CY2022	iclr	Increase Decrease In Contract With Customer Liability Gross Current Percent IncreaseDecreaseInContractWithCustomerLiabilityGrossCurrentPercent	0.139
CY2022Q4	iclr	Advance Payments Netted Against Unbilled Contracts Receivable AdvancePaymentsNettedAgainstUnbilledContractsReceivable	-549794000	usd
CY2021Q4	iclr	Advance Payments Netted Against Unbilled Contracts Receivable AdvancePaymentsNettedAgainstUnbilledContractsReceivable	-700840000	usd
CY2022	iclr	Changein Advance Payments Netted Against Unbilled Contracts Receivable ChangeinAdvancePaymentsNettedAgainstUnbilledContractsReceivable	151046000	usd
CY2022	iclr	Changein Advance Payments Netted Against Unbilled Contracts Receivable Percent ChangeinAdvancePaymentsNettedAgainstUnbilledContractsReceivablePercent	0.216
CY2022Q4	iclr	Other Liabilities Amount Payable To Third Parties For Reimbursable Expenses OtherLiabilitiesAmountPayableToThirdPartiesForReimbursableExpenses	406300000	usd
CY2021Q4	iclr	Other Liabilities Amount Payable To Third Parties For Reimbursable Expenses OtherLiabilitiesAmountPayableToThirdPartiesForReimbursableExpenses	323600000	usd
CY2022	iclr	Increase Decrease In Contractwith Customer Asset Gross Current IncreaseDecreaseInContractwithCustomerAssetGrossCurrent	334500000	usd
CY2022	iclr	Increase Decrease In Contracts With Customers Liability Current IncreaseDecreaseInContractsWithCustomersLiabilityCurrent	183500000	usd
CY2022	iclr	Changein Advance Payments Netted Against Unbilled Contracts Receivable ChangeinAdvancePaymentsNettedAgainstUnbilledContractsReceivable	151000000	usd
CY2022	us-gaap	Contract With Customer Asset Credit Loss Expense ContractWithCustomerAssetCreditLossExpense	17800000	usd
CY2021	us-gaap	Contract With Customer Asset Credit Loss Expense ContractWithCustomerAssetCreditLossExpense	900000	usd
CY2022Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	13700000000	usd
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	13300000000	usd
CY2022Q4	us-gaap	Revenue Remaining Performance Obligation Percentage RevenueRemainingPerformanceObligationPercentage	0.52
CY2022Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P12M
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P12M
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation Percentage RevenueRemainingPerformanceObligationPercentage	0.48
CY2021Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	7081000	usd
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	7149000	usd
CY2022	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	3913000	usd
CY2021	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	116000	usd
CY2022	iclr	Accounts Receivable Credit Loss Expense AccountsReceivableCreditLossExpense	17800000	usd
CY2021	iclr	Accounts Receivable Credit Loss Expense AccountsReceivableCreditLossExpense	705000	usd
CY2022	iclr	Accounts Receivable Credit Loss Reversal AccountsReceivableCreditLossReversal	0	usd
CY2021	iclr	Accounts Receivable Credit Loss Reversal AccountsReceivableCreditLossReversal	544000	usd
CY2022	iclr	Allowance For Doubtful Accounts Foreign Currency Translation Adjustments AllowanceForDoubtfulAccountsForeignCurrencyTranslationAdjustments	-406000	usd
CY2021	iclr	Allowance For Doubtful Accounts Foreign Currency Translation Adjustments AllowanceForDoubtfulAccountsForeignCurrencyTranslationAdjustments	-113000	usd
CY2022Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	20562000	usd
CY2021Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	7081000	usd
CY2021Q3	dei	Entity Number Of Employees EntityNumberOfEmployees	38000	employee
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	1713000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	32663000	usd
CY2022Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	34388000	usd
CY2022Q4	us-gaap	Liabilities Fair Value Disclosure LiabilitiesFairValueDisclosure	3670000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	1712000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	20579000	usd
CY2021Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	22291000	usd
CY2022Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	4650300000	usd
CY2021Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	5507200000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	1700000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	1700000	usd
CY2022	iclr	Short Term Available For Sale Investments Average Remaining Maturity Period ShortTermAvailableForSaleInvestmentsAverageRemainingMaturityPeriod	P2Y9M18D
CY2021	iclr	Short Term Available For Sale Investments Average Remaining Maturity Period ShortTermAvailableForSaleInvestmentsAverageRemainingMaturityPeriod	P2Y8M12D
CY2022Q4	iclr	Debt Securities Available For Sale Cumulative Amount Advanced Under Subscription Agreements DebtSecuritiesAvailableForSaleCumulativeAmountAdvancedUnderSubscriptionAgreements	20600000	usd
CY2021Q4	iclr	Debt Securities Available For Sale Cumulative Amount Advanced Under Subscription Agreements DebtSecuritiesAvailableForSaleCumulativeAmountAdvancedUnderSubscriptionAgreements	16900000	usd
CY2022	us-gaap	Increase Decrease In Equity Securities Fv Ni IncreaseDecreaseInEquitySecuritiesFvNi	6300000	usd
CY2021	us-gaap	Increase Decrease In Equity Securities Fv Ni IncreaseDecreaseInEquitySecuritiesFvNi	3200000	usd
CY2022Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	32600000	usd
CY2021Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	22600000	usd
CY2022Q4	iclr	Commitment To Acquire Long Term Investments CommitmentToAcquireLongTermInvestments	23300000	usd
CY2020Q3	us-gaap	Equity Method Investments EquityMethodInvestments	4900000	usd
CY2022Q4	iclr	Equity Method Investment Majority Ownership Percentage EquityMethodInvestmentMajorityOwnershipPercentage	0.51
CY2022	iclr	Equity Method Investment Period Majority Voting Share Capital Can Be Sold To The Company EquityMethodInvestmentPeriodMajorityVotingShareCapitalCanBeSoldToTheCompany	P18M
CY2022Q4	iclr	Equity Method Investment Majority Ownership Percentage EquityMethodInvestmentMajorityOwnershipPercentage	0.51
CY2022Q4	us-gaap	Equity Method Investments EquityMethodInvestments	0	usd
CY2021Q4	us-gaap	Equity Method Investments EquityMethodInvestments	2373000	usd
CY2022Q4	us-gaap	Land Land	3724000	usd
CY2021Q4	us-gaap	Land Land	3724000	usd
CY2022Q4	us-gaap	Buildings And Improvements Gross BuildingsAndImprovementsGross	70880000	usd
CY2021Q4	us-gaap	Buildings And Improvements Gross BuildingsAndImprovementsGross	82017000	usd
CY2022Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	500135000	usd
CY2021Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	506322000	usd
CY2022Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	50600000	usd
CY2021Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	107507000	usd
CY2022Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	59946000	usd
CY2021Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	29210000	usd
CY2022Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	65167000	usd
CY2021Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	70123000	usd
CY2022Q4	iclr	Vehicles Gross VehiclesGross	41000	usd
CY2021Q4	iclr	Vehicles Gross VehiclesGross	65000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	750493000	usd
CY2021Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	798968000	usd
CY2022Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	400173000	usd
CY2021Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	462524000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	350320000	usd
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	336444000	usd
CY2022	us-gaap	Depreciation Depreciation	106426000	usd
CY2021	us-gaap	Depreciation Depreciation	75484000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	9037931000	usd
CY2020Q4	us-gaap	Goodwill Goodwill	936257000	usd
CY2022	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	usd
CY2021	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	8120006000	usd
CY2022	us-gaap	Goodwill Purchase Accounting Adjustments GoodwillPurchaseAccountingAdjustments	-35692000	usd
CY2021	us-gaap	Goodwill Purchase Accounting Adjustments GoodwillPurchaseAccountingAdjustments	0	usd
CY2022	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-30569000	usd
CY2021	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-18332000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	8971670000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	9037931000	usd
CY2021	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2022	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	5109212000	usd
CY2021Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	5081381000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	830553000	usd
CY2021Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	370538000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	4278659000	usd
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	4710843000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	460711000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	339940000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	223674000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	209681000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	198300000	usd
CY2022Q4	iclr	Finite Lived Intangible Assets Amortization Expense Net FiniteLivedIntangibleAssetsAmortizationExpenseNet	1432306000	usd
CY2022Q4	us-gaap	Other Sundry Liabilities Current OtherSundryLiabilitiesCurrent	530204000	usd
CY2021Q4	us-gaap	Other Sundry Liabilities Current OtherSundryLiabilitiesCurrent	459814000	usd
CY2022Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	395862000	usd
CY2021Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	413185000	usd
CY2022Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	43657000	usd
CY2021Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	49949000	usd
CY2022Q4	us-gaap	Accrued Utilities Current AccruedUtilitiesCurrent	16896000	usd
CY2021Q4	us-gaap	Accrued Utilities Current AccruedUtilitiesCurrent	12055000	usd
CY2022Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	12852000	usd
CY2021Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	7204000	usd
CY2022Q4	iclr	Restructuring Reserveand Other Liabilities Current RestructuringReserveandOtherLiabilitiesCurrent	5512000	usd
CY2021Q4	iclr	Restructuring Reserveand Other Liabilities Current RestructuringReserveandOtherLiabilitiesCurrent	7377000	usd
CY2022Q4	iclr	Capital Government Grants Current CapitalGovernmentGrantsCurrent	42000	usd
CY2021Q4	iclr	Capital Government Grants Current CapitalGovernmentGrantsCurrent	45000	usd
CY2022Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	1005025000	usd
CY2021Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	949629000	usd
CY2022Q4	iclr	Other Liabilities Amount Payable To Third Parties For Reimbursable Expenses OtherLiabilitiesAmountPayableToThirdPartiesForReimbursableExpenses	406300000	usd
CY2021Q4	iclr	Other Liabilities Amount Payable To Third Parties For Reimbursable Expenses OtherLiabilitiesAmountPayableToThirdPartiesForReimbursableExpenses	323600000	usd
CY2022Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	4701213000	usd
CY2021Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	5501213000	usd
CY2022Q4	iclr	Long Term Debt Current Maturities Gross LongTermDebtCurrentMaturitiesGross	55150000	usd
CY2021Q4	iclr	Long Term Debt Current Maturities Gross LongTermDebtCurrentMaturitiesGross	55150000	usd
CY2022Q4	iclr	Long Term Debt Excluding Current Maturities Gross LongTermDebtExcludingCurrentMaturitiesGross	4646063000	usd
CY2021Q4	iclr	Long Term Debt Excluding Current Maturities Gross LongTermDebtExcludingCurrentMaturitiesGross	5446063000	usd
CY2022Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	47026000	usd
CY2021Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	64901000	usd
CY2022Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	4599037000	usd
CY2021Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	5381162000	usd
CY2022	us-gaap	Interest Expense Debt InterestExpenseDebt	209189000	usd
CY2021	us-gaap	Interest Expense Debt InterestExpenseDebt	93809000	usd
CY2020	us-gaap	Interest Expense Debt InterestExpenseDebt	13406000	usd
CY2022	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	17749000	usd
CY2021	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	12890000	usd
CY2020	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	523000	usd
CY2022	iclr	Transaction And One Time Financing Costs TransactionAndOneTimeFinancingCosts	0	usd
CY2021	iclr	Transaction And One Time Financing Costs TransactionAndOneTimeFinancingCosts	75391000	usd
CY2020	iclr	Transaction And One Time Financing Costs TransactionAndOneTimeFinancingCosts	0	usd
CY2022	iclr	Interest Expense Credit Other InterestExpenseCreditOther	2793000	usd
CY2021	iclr	Interest Expense Credit Other InterestExpenseCreditOther	333000	usd
CY2020	iclr	Interest Expense Credit Other InterestExpenseCreditOther	-910000	usd
CY2022	us-gaap	Interest Expense InterestExpense	229731000	usd
CY2021	us-gaap	Interest Expense InterestExpense	182423000	usd
CY2020	us-gaap	Interest Expense InterestExpense	13019000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	55150000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	55150000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	55150000	usd
CY2022Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	55150000	usd
CY2022Q4	iclr	Long Term Debt Maturity Year Five And Thereafter LongTermDebtMaturityYearFiveAndThereafter	4480613000	usd
CY2022Q4	us-gaap	Long Term Debt LongTermDebt	4701213000	usd
CY2022Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	4650300000	usd
CY2021Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	5507200000	usd
CY2022Q4	us-gaap	Interest Rate Cash Flow Hedge Gain Loss To Be Reclassified During Next12 Months Net InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet	-3300000	usd
CY2021Q4	us-gaap	Derivative Fair Value Of Derivative Net DerivativeFairValueOfDerivativeNet	0	usd
CY2021Q4	us-gaap	Derivative Number Of Instruments Held DerivativeNumberOfInstrumentsHeld	0	tranche
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	100000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	100000	usd
CY2022	us-gaap	Operating Lease Cost OperatingLeaseCost	53880000	usd
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	51200000	usd
CY2022	us-gaap	Sublease Income SubleaseIncome	1165000	usd
CY2021	us-gaap	Sublease Income SubleaseIncome	1338000	usd
CY2022	us-gaap	Lease Cost LeaseCost	52715000	usd
CY2021	us-gaap	Lease Cost LeaseCost	49862000	usd
CY2022	us-gaap	Lease Cost LeaseCost	52700000	usd
CY2021	us-gaap	Lease Cost LeaseCost	49900000	usd
CY2022	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	28700000	usd
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	10200000	usd
CY2022	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	24800000	usd
CY2021	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	15400000	usd
CY2022Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P6Y10M24D
CY2022Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0245
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P6Y10M28D
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0251
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	47479000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	34400000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	25045000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	20430000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	17249000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	45065000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	189668000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	14367000	usd
CY2022Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	175301000	usd
CY2022Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	43700000	usd
CY2021Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	49900000	usd
CY2022Q4	us-gaap	Defined Benefit Pension Plan Liabilities Noncurrent DefinedBenefitPensionPlanLiabilitiesNoncurrent	13033000	usd
CY2021Q4	us-gaap	Defined Benefit Pension Plan Liabilities Noncurrent DefinedBenefitPensionPlanLiabilitiesNoncurrent	16262000	usd
CY2022Q4	us-gaap	Other Sundry Liabilities Noncurrent OtherSundryLiabilitiesNoncurrent	25227000	usd
CY2021Q4	us-gaap	Other Sundry Liabilities Noncurrent OtherSundryLiabilitiesNoncurrent	26334000	usd
CY2022Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	38260000	usd
CY2021Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	42596000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Term Of Contract LesseeOperatingLeaseTermOfContract	P12Y
CY2022	iclr	Number Of Votes NumberOfVotes	1	vote
CY2022	iclr	Number Of Votes NumberOfVotes	1	vote
CY2022	us-gaap	Restructuring Costs RestructuringCosts	31143000	usd
CY2021	us-gaap	Restructuring Costs RestructuringCosts	31105000	usd
CY2020	us-gaap	Restructuring Costs RestructuringCosts	18089000	usd
CY2022	us-gaap	Restructuring Costs RestructuringCosts	31143000	usd
CY2021	us-gaap	Restructuring Costs RestructuringCosts	31105000	usd
CY2020	us-gaap	Restructuring Costs RestructuringCosts	18089000	usd
CY2022Q4	us-gaap	Restructuring Reserve RestructuringReserve	6000000	usd
CY2021Q4	us-gaap	Restructuring Reserve RestructuringReserve	10311000	usd
CY2020Q4	us-gaap	Restructuring Reserve RestructuringReserve	4675000	usd
CY2022	us-gaap	Restructuring Charges RestructuringCharges	4364000	usd
CY2021	us-gaap	Restructuring Charges RestructuringCharges	11273000	usd
CY2022	iclr	Restructuring Reserve Utilizations RestructuringReserveUtilizations	8653000	usd
CY2021	iclr	Restructuring Reserve Utilizations RestructuringReserveUtilizations	5637000	usd
CY2022Q4	us-gaap	Restructuring Reserve RestructuringReserve	6022000	usd
CY2021Q4	us-gaap	Restructuring Reserve RestructuringReserve	10311000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	567851000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	196680000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	381205000	usd
CY2022	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	184396000	usd
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	101950000	usd
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	46948000	usd
CY2022	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	70980000	usd
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	24586000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-124985000	usd
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-60616000	usd
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	927000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	59411000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	41334000	usd
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	47875000	usd
CY2022	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	7211000	usd
CY2021	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	1776000	usd
CY2020	us-gaap	Other Comprehensive Income Foreign Currency Translation Gain Loss Arising During Period Tax OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax	68000	usd
CY2022	us-gaap	Income Tax Effects Allocated Directly To Equity IncomeTaxEffectsAllocatedDirectlyToEquity	66622000	usd
CY2021	us-gaap	Income Tax Effects Allocated Directly To Equity IncomeTaxEffectsAllocatedDirectlyToEquity	43110000	usd
CY2020	us-gaap	Income Tax Effects Allocated Directly To Equity IncomeTaxEffectsAllocatedDirectlyToEquity	47943000	usd
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	47651000	usd
CY2022	us-gaap	Income Tax Reconciliation Nondeductible Expense Amortization IncomeTaxReconciliationNondeductibleExpenseAmortization	-59330000	usd
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Amortization IncomeTaxReconciliationNondeductibleExpenseAmortization	-31228000	usd
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Amortization IncomeTaxReconciliationNondeductibleExpenseAmortization	-2298000	usd
CY2022	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	52464000	usd
CY2021	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	51273000	usd
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	10241000	usd
CY2022	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	2608000	usd
CY2021	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	3120000	usd
CY2020	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	1243000	usd
CY2022	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-777000	usd
CY2021	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	3101000	usd
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	3581000	usd
CY2022	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-300000	usd
CY2021	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-128000	usd
CY2020	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	108000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Period Increase Decrease UnrecognizedTaxBenefitsPeriodIncreaseDecrease	8392000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Period Increase Decrease UnrecognizedTaxBenefitsPeriodIncreaseDecrease	5246000	usd
CY2020	us-gaap	Unrecognized Tax Benefits Period Increase Decrease UnrecognizedTaxBenefitsPeriodIncreaseDecrease	-1672000	usd
CY2022	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-8756000	usd
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-9083000	usd
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-5150000	usd
CY2022	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	-654000	usd
CY2021	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	687000	usd
CY2020	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	-3343000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	59411000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	41334000	usd
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	47875000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	10927000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	19606000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	23260000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	33449000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Goodwill DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsGoodwill	37150000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Goodwill DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsGoodwill	33354000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Other Finite Lived Assets DeferredTaxLiabilitiesOtherFiniteLivedAssets	1078302000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Other Finite Lived Assets DeferredTaxLiabilitiesOtherFiniteLivedAssets	1201086000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	9054000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	1761000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	1158693000	usd
CY2021Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	1289256000	usd
CY2022Q4	iclr	Deferred Tax Assets Operating Loss And Tax Credits Carryforwards DeferredTaxAssetsOperatingLossAndTaxCreditsCarryforwards	88697000	usd
CY2021Q4	iclr	Deferred Tax Assets Operating Loss And Tax Credits Carryforwards DeferredTaxAssetsOperatingLossAndTaxCreditsCarryforwards	86893000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	6010000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	5846000	usd
CY2022Q4	iclr	Deferred Tax Assets Operating Lease Liability DeferredTaxAssetsOperatingLeaseLiability	27593000	usd
CY2021Q4	iclr	Deferred Tax Assets Operating Lease Liability DeferredTaxAssetsOperatingLeaseLiability	36106000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Goodwill And Intangible Assets DeferredTaxAssetsGoodwillAndIntangibleAssets	3602000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Goodwill And Intangible Assets DeferredTaxAssetsGoodwillAndIntangibleAssets	4596000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	64016000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	69198000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Other DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsOther	21862000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Other DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsOther	25557000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	2917000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	3445000	usd
CY2022Q4	iclr	Deferred Tax Asset Contract With Customer Liability DeferredTaxAssetContractWithCustomerLiability	66565000	usd
CY2021Q4	iclr	Deferred Tax Asset Contract With Customer Liability DeferredTaxAssetContractWithCustomerLiability	64924000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	9155000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	602000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	290417000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	297167000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	43379000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	45495000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	247038000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	251672000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	911655000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	1037584000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	43400000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	45500000	usd
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	32800000	usd
CY2022	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	-2100000	usd
CY2021	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	12800000	usd
CY2022	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	-2100000	usd
CY2021	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	12800000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	1600000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	800000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	202065000	usd
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	19078000	usd
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	20156000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition		usd
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	170047000	usd
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	0	usd
CY2022	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	16098000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	204000	usd
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	401000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	5442000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	1695000	usd
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	1271000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	5701000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	18613000	usd
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	2931000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	usd
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	844000	usd
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	369000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	838000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	3338000	usd
CY2020	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	2770000	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	217584000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	202065000	usd
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	19078000	usd
CY2022Q4	us-gaap	Significant Change In Unrecognized Tax Benefits Is Reasonably Possible Amount Of Unrecorded Benefit SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit	37900000	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	217600000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	202100000	usd
CY2020Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	19100000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	7100000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	1900000	usd
CY2020	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	600000	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	22600000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	15500000	usd
CY2022	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y8M8D
CY2022	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1	P4Y3M
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P5Y4M20D
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1	P4Y6M18D
CY2022	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Lower Range Limit ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit	14.88
CY2022	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Upper Range Limit ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit	231.68
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	70500000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	70523000	usd
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	133844000	usd
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	26271000	usd
CY2022	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	12900000	usd
CY2022	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	7700000	usd
CY2021	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	22700000	usd
CY2021	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	23900000	usd
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	6900000	usd
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Exercise Of Stock Options EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions	2500000	usd
CY2022	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	segment
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	7741386000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	5480826000	usd
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2797288000	usd
CY2022	iclr	Operating Income Loss Before Restructuring Charges Transaction And Integration Expenses OperatingIncomeLossBeforeRestructuringChargesTransactionAndIntegrationExpenses	795237000	usd
CY2021	iclr	Operating Income Loss Before Restructuring Charges Transaction And Integration Expenses OperatingIncomeLossBeforeRestructuringChargesTransactionAndIntegrationExpenses	378529000	usd
CY2020	iclr	Operating Income Loss Before Restructuring Charges Transaction And Integration Expenses OperatingIncomeLossBeforeRestructuringChargesTransactionAndIntegrationExpenses	391500000	usd
CY2022Q4	us-gaap	Noncurrent Assets NoncurrentAssets	504152000	usd
CY2021Q4	us-gaap	Noncurrent Assets NoncurrentAssets	534567000	usd
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	81532320	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	67110186	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	52859911	shares
CY2022	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	936043	shares
CY2021	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	958125	shares
CY2020	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	423674	shares
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	82468363	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	68068311	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53283585	shares
CY2022	us-gaap	Net Income Loss NetIncomeLoss	505304000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	153185000	usd
CY2020	us-gaap	Net Income Loss NetIncomeLoss	332331000	usd
CY2022	us-gaap	Temporary Equity Accretion To Redemption Value Adjustment TemporaryEquityAccretionToRedemptionValueAdjustment	0	usd
CY2021	us-gaap	Temporary Equity Accretion To Redemption Value Adjustment TemporaryEquityAccretionToRedemptionValueAdjustment	0	usd
CY2020	us-gaap	Temporary Equity Accretion To Redemption Value Adjustment TemporaryEquityAccretionToRedemptionValueAdjustment	4522000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	505304000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	153185000	usd
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	327809000	usd
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.20
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.28
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.20
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.13
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.25
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.15
CY2021	us-gaap	Interest Paid Net InterestPaidNet	106205000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	-175369000	usd
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	-85840000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	-7559000	usd
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	5098000	usd
CY2022Q4	iclr	Acumulated Other Comprehensive Loss Cash Flow Hedge Loss Reclassification After Tax AcumulatedOtherComprehensiveLossCashFlowHedgeLossReclassificationAfterTax	-3728000	usd
CY2021Q4	iclr	Acumulated Other Comprehensive Loss Cash Flow Hedge Loss Reclassification After Tax AcumulatedOtherComprehensiveLossCashFlowHedgeLossReclassificationAfterTax	0	usd
CY2022Q4	iclr	Accumulated Other Comprehensive Loss Amortization Of Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveLossAmortizationOfCashFlowHedgesEffectNetOfTax	0	usd
CY2021Q4	iclr	Accumulated Other Comprehensive Loss Amortization Of Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveLossAmortizationOfCashFlowHedgesEffectNetOfTax	1000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-171538000	usd
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-90937000	usd
CY2022	us-gaap	Interest Paid Net InterestPaidNet	210918000	usd
CY2020	us-gaap	Interest Paid Net InterestPaidNet	13062000	usd
CY2022	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	116322000	usd
CY2021	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	55105000	usd
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	27604000	usd
CY2020Q3	us-gaap	Equity Method Investments EquityMethodInvestments	4900000	usd
CY2022Q4	iclr	Equity Method Investment Majority Ownership Percentage EquityMethodInvestmentMajorityOwnershipPercentage	0.51
CY2022Q4	iclr	Equity Method Investment Majority Ownership Percentage EquityMethodInvestmentMajorityOwnershipPercentage	0.51

Files In Submission

Name	View Source	Status
0001060955-23-000007-index-headers.html	Edgar Link	pending
0001060955-23-000007-index.html	Edgar Link	pending
0001060955-23-000007.txt	Edgar Link	pending
0001060955-23-000007-xbrl.zip	Edgar Link	pending
exhibit121-2022.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
iclr-20221231_cal.xml	Edgar Link	unprocessable
exhibit122-2022.htm	Edgar Link	pending
exhibit22-2022.htm	Edgar Link	pending
exhibit231-2022.htm	Edgar Link	pending
exhibit25-2022.htm	Edgar Link	pending
Financial_Report.xlsx	Edgar Link	pending
iclr-20221231.htm	Edgar Link	pending
iclr-20221231.xsd	Edgar Link	pending
iclr-20221231_g1.jpg	Edgar Link	pending
iclr-20221231_g10.jpg	Edgar Link	pending
iclr-20221231_g11.jpg	Edgar Link	pending
iclr-20221231_g2.jpg	Edgar Link	pending
iclr-20221231_g3.jpg	Edgar Link	pending
iclr-20221231_g4.jpg	Edgar Link	pending
iclr-20221231_g5.jpg	Edgar Link	pending
iclr-20221231_g6.jpg	Edgar Link	pending
iclr-20221231_g7.jpg	Edgar Link	pending
iclr-20221231_g8.jpg	Edgar Link	pending
iclr-20221231_g9.jpg	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R100.htm	Edgar Link	pending
R101.htm	Edgar Link	pending
R102.htm	Edgar Link	pending
R103.htm	Edgar Link	pending
R104.htm	Edgar Link	pending
R105.htm	Edgar Link	pending
R106.htm	Edgar Link	pending
R107.htm	Edgar Link	pending
R108.htm	Edgar Link	pending
R109.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
R110.htm	Edgar Link	pending
R111.htm	Edgar Link	pending
R112.htm	Edgar Link	pending
R113.htm	Edgar Link	pending
R114.htm	Edgar Link	pending
R115.htm	Edgar Link	pending
R116.htm	Edgar Link	pending
R117.htm	Edgar Link	pending
R118.htm	Edgar Link	pending
R119.htm	Edgar Link	pending
R12.htm	Edgar Link	pending
R120.htm	Edgar Link	pending
R121.htm	Edgar Link	pending
R122.htm	Edgar Link	pending
iclr-20221231_def.xml	Edgar Link	unprocessable
iclr-20221231_lab.xml	Edgar Link	unprocessable
iclr-20221231_pre.xml	Edgar Link	unprocessable
iclr-20221231_htm.xml	Edgar Link	completed
R123.htm	Edgar Link	pending
R124.htm	Edgar Link	pending
R125.htm	Edgar Link	pending
R126.htm	Edgar Link	pending
R127.htm	Edgar Link	pending
R128.htm	Edgar Link	pending
R129.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R130.htm	Edgar Link	pending
R131.htm	Edgar Link	pending
R132.htm	Edgar Link	pending
R133.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
R19.htm	Edgar Link	pending
R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
R32.htm	Edgar Link	pending
R33.htm	Edgar Link	pending
R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
R36.htm	Edgar Link	pending
R37.htm	Edgar Link	pending
R38.htm	Edgar Link	pending
R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R58.htm	Edgar Link	pending
R59.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R60.htm	Edgar Link	pending
R61.htm	Edgar Link	pending
R62.htm	Edgar Link	pending
R63.htm	Edgar Link	pending
R64.htm	Edgar Link	pending
R65.htm	Edgar Link	pending
R66.htm	Edgar Link	pending
R67.htm	Edgar Link	pending
R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R70.htm	Edgar Link	pending
R71.htm	Edgar Link	pending
R72.htm	Edgar Link	pending
R73.htm	Edgar Link	pending
R74.htm	Edgar Link	pending
R75.htm	Edgar Link	pending
R76.htm	Edgar Link	pending
R77.htm	Edgar Link	pending
R78.htm	Edgar Link	pending
R79.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R80.htm	Edgar Link	pending
R81.htm	Edgar Link	pending
R82.htm	Edgar Link	pending
R83.htm	Edgar Link	pending
R84.htm	Edgar Link	pending
R85.htm	Edgar Link	pending
R86.htm	Edgar Link	pending
R87.htm	Edgar Link	pending
R88.htm	Edgar Link	pending
R89.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
R90.htm	Edgar Link	pending
R91.htm	Edgar Link	pending
R92.htm	Edgar Link	pending
R93.htm	Edgar Link	pending
R94.htm	Edgar Link	pending
R95.htm	Edgar Link	pending
R96.htm	Edgar Link	pending
R97.htm	Edgar Link	pending
R98.htm	Edgar Link	pending
R99.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending

Create your account

Find Stocks Worth Researching

Deeply Understand Businesses

Value Businesses Intelligently

$ICLR
ICON PLC Stock $iclr

2022 Q4 Form 20-F Financial Statement

#000106095523000007 Filed on February 24, 2023

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$ICLR ICON PLC Stock $iclr

2022 Q4 Form 20-F Financial Statement

#000106095523000007 Filed on February 24, 2023

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$ICLR
ICON PLC Stock $iclr