$TTEK
TETRA TECH INC Stock $ttek

$ttek Overview Financials Valuation SEC Filings Company Website

2023 Q4 Form 10-K Financial Statement

#000083164123000082 Filed on November 22, 2023

Income Statement

Concept	2023 Q4	2023	2022
Revenue	$1.261B	$4.523B	$2.836B
YoY Change	71.25%	59.49%	-11.76%
Cost Of Revenue	$845.3M	$3.026B	$2.260B
YoY Change	45.72%	33.9%	10.04%
Gross Profit	$190.5M	$725.0M	$575.6M
YoY Change	22.09%	25.97%	15.48%
Gross Profit Margin	15.11%	16.03%	20.3%
Selling, General & Admin	$77.20M	$305.1M	$235.1M
YoY Change	26.07%	29.77%	5.45%
% of Gross Profit	40.52%	42.08%	40.85%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$19.48M	$61.21M	$27.03M
YoY Change	160.2%	126.41%	13.56%
% of Gross Profit	10.23%	8.44%	4.7%
Operating Expenses	$80.97M	$317.4M	$235.1M
YoY Change	32.24%	34.98%	7.02%
Operating Profit	$107.4M	$358.1M	$340.4M
YoY Change	13.26%	5.19%	22.15%
Interest Expense	-$12.97M	$52.44M	-$11.58M
YoY Change	395.57%	-552.65%	-190.87%
% of Operating Profit	-12.08%	14.64%	-3.4%
Other Income/Expense, Net	$0.00	$89.40M	$19.90M
YoY Change	-100.0%	349.17%
Pretax Income	$101.5M	$401.0M	$348.8M
YoY Change	-9.44%	14.97%	30.69%
Income Tax	$26.52M	$127.5M	$85.60M
% Of Pretax Income	26.13%	31.8%	24.54%
Net Earnings	$74.98M	$273.5M	$263.1M
YoY Change	-9.6%	3.92%	13.01%
Net Earnings / Revenue	5.95%	6.05%	9.28%
Basic Earnings Per Share	$1.01	$5.14	$4.91
Diluted Earnings Per Share	$1.00	$5.10	$4.858M
COMMON SHARES
Basic Shares Outstanding	53.25M shares	53.20M shares	53.62M shares
Diluted Shares Outstanding	53.70M shares	53.64M shares	54.16M shares

Balance Sheet

Concept	2023 Q4	2023	2022
SHORT-TERM ASSETS
Cash & Short-Term Investments	$168.8M	$168.8M	$185.1M
YoY Change	-8.79%	-8.79%	11.12%
Cash & Equivalents	$168.8M	$168.8M	$185.1M
Short-Term Investments
Other Short-Term Assets	$89.10M	$89.10M	$115.4M
YoY Change	-22.79%	-22.79%	2.73%
Inventory
Prepaid Expenses
Receivables	$974.5M	$1.088B	$847.5M
Other Receivables	$9.623M	$9.623M	$10.20M
Total Short-Term Assets	$1.356B	$1.356B	$1.158B
YoY Change	17.08%	17.08%	8.66%
LONG-TERM ASSETS
Property, Plant & Equipment	$74.83M	$250.8M	$214.6M
YoY Change	-65.14%	16.83%	-15.22%
Goodwill	$1.880B
YoY Change	69.33%
Intangibles
YoY Change
Long-Term Investments			$4.570M
YoY Change			39.24%
Other Assets	$70.51M	$159.5M	$105.8M
YoY Change	-33.35%	50.79%	-1.7%
Total Long-Term Assets	$2.464B	$2.464B	$1.465B
YoY Change	68.27%	68.27%	-3.05%
TOTAL ASSETS
Total Short-Term Assets	$1.356B	$1.356B	$1.158B
Total Long-Term Assets	$2.464B	$2.464B	$1.465B
Total Assets	$3.820B	$3.820B	$2.623B
YoY Change	45.67%	45.67%	1.79%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$173.3M	$173.3M	$147.4M
YoY Change	17.52%	17.52%	14.5%
Accrued Expenses	$367.8M	$367.8M	$295.5M
YoY Change	24.44%	24.44%	7.95%
Deferred Revenue	$335.0M
YoY Change	38.83%
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$0.00	$0.00	$12.50M
YoY Change	-100.0%	-100.0%	0.0%
Total Short-Term Liabilities	$1.208B	$1.208B	$916.0M
YoY Change	31.89%	31.89%	7.96%
LONG-TERM LIABILITIES
Long-Term Debt	$879.5M	$879.5M	$246.3M
YoY Change	257.17%	257.17%	23.13%
Other Long-Term Liabilities	$148.0M	$315.0M	$262.2M
YoY Change	-43.54%	20.15%	-7.42%
Total Long-Term Liabilities	$1.028B	$1.195B	$508.5M
YoY Change	102.09%	134.94%	5.22%
TOTAL LIABILITIES
Total Short-Term Liabilities	$1.208B	$1.208B	$916.0M
Total Long-Term Liabilities	$1.028B	$1.195B	$508.5M
Total Liabilities	$2.236B	$2.417B	$1.440B
YoY Change	55.29%	67.89%	7.25%
SHAREHOLDERS EQUITY
Retained Earnings	$1.598B
YoY Change	14.92%
Common Stock	$532.0K
YoY Change	0.38%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$1.403B	$1.403B	$1.183B
YoY Change
Total Liabilities & Shareholders Equity	$3.820B	$3.820B	$2.623B
YoY Change	45.67%	45.67%	1.79%

Cashflow Statement

Concept	2023 Q4	2023	2022
OPERATING ACTIVITIES
Net Income	$74.98M	$273.5M	$263.1M
YoY Change	-9.6%	3.92%	13.01%
Depreciation, Depletion And Amortization	$19.48M	$61.21M	$27.03M
YoY Change	160.2%	126.41%	13.56%
Cash From Operating Activities	$9.246M	$368.5M	$336.2M
YoY Change	-84.64%	9.6%	10.45%
INVESTING ACTIVITIES
Capital Expenditures	$3.456M	$26.90M	-$10.58M
YoY Change	-258.46%	-354.21%	-223.43%
Acquisitions		$854.3M	$49.12M
YoY Change		1639.11%	-42.15%
Other Investing Activities	$302.0K	-$744.3M	-$45.16M
YoY Change	-101.98%	1548.21%	-46.51%
Cash From Investing Activities	-$3.434M	-$771.2M	-$55.74M
YoY Change	-80.34%	1283.56%	-40.06%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$0.00	-$198.2M
YoY Change		-100.0%	-430.32%
Debt Paid & Issued, Net	$60.00M		$117.1M
YoY Change			-71.74%
Cash From Financing Activities	$18.39M	$382.4M	-249.6M
YoY Change	-127.4%	-253.19%	18.8%
NET CHANGE
Cash From Operating Activities	$9.246M	$368.5M	336.2M
Cash From Investing Activities	-$3.434M	-$771.2M	-55.74M
Cash From Financing Activities	$18.39M	$382.4M	-249.6M
Net Change In Cash	$29.86M	-$16.26M	30.84M
YoY Change	-222.47%	-152.73%	240.66%
FREE CASH FLOW
Cash From Operating Activities	$9.246M	$368.5M	$336.2M
Capital Expenditures	$3.456M	$26.90M	-$10.58M
Free Cash Flow	$5.790M	$341.6M	$346.8M
YoY Change	-90.72%	-1.5%	17.23%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2023	dei	Entity Central Index Key EntityCentralIndexKey	0000831641
CY2023	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2023
CY2023	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2023	dei	Amendment Flag AmendmentFlag	false
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CY2022	us-gaap	Fair Value Recurring Basis Unobservable Input Reconciliation Liability Gain Loss Statement Of Income Extensible List FairValueRecurringBasisUnobservableInputReconciliationLiabilityGainLossStatementOfIncomeExtensibleList	http://fasb.org/us-gaap/2023#OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax
CY2023	us-gaap	Fair Value Recurring Basis Unobservable Input Reconciliation Liability Gain Loss Statement Of Income Extensible List FairValueRecurringBasisUnobservableInputReconciliationLiabilityGainLossStatementOfIncomeExtensibleList	http://fasb.org/us-gaap/2023#OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax
CY2023Q4	us-gaap	Government Assistance Current Statement Of Financial Position Extensible Enumeration GovernmentAssistanceCurrentStatementOfFinancialPositionExtensibleEnumeration	http://fasb.org/us-gaap/2023#OtherLiabilitiesCurrent
CY2023Q4	us-gaap	Government Assistance Noncurrent Statement Of Financial Position Extensible Enumeration GovernmentAssistanceNoncurrentStatementOfFinancialPositionExtensibleEnumeration	http://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrent
CY2023Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1
CY2023	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--10-01
CY2023	dei	Entity Shell Company EntityShellCompany	false
CY2022Q4	us-gaap	Contract With Customer Asset Net Current ContractWithCustomerAssetNetCurrent	92405000	usd
CY2023Q2	dei	Entity Public Float EntityPublicFloat	7700000000	usd
CY2023Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	53247668	shares
CY2022	dei	Auditor Name AuditorName	PricewaterhouseCoopers LLP
CY2023	dei	Auditor Location AuditorLocation	Los Angeles, California
CY2022Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	185094000	usd
CY2022Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	755112000	usd
CY2022Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	115400000	usd
CY2022Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	10205000	usd
CY2022Q4	us-gaap	Assets Current AssetsCurrent	1158216000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	32316000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	182319000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	1110412000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	29163000	usd
CY2022Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	47804000	usd
CY2022Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	62546000	usd
CY2022Q4	us-gaap	Assets Assets	2622776000	usd
CY2022Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	147436000	usd
CY2022Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	237669000	usd
CY2022Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	241340000	usd
CY2022Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	57865000	usd
CY2023Q4	us-gaap	Debt Current DebtCurrent	0	usd
CY2022Q4	us-gaap	Debt Current DebtCurrent	12504000	usd
CY2023Q4	us-gaap	Business Combination Contingent Consideration Liability Current BusinessCombinationContingentConsiderationLiabilityCurrent	51108000	usd
CY2022Q4	us-gaap	Business Combination Contingent Consideration Liability Current BusinessCombinationContingentConsiderationLiabilityCurrent	28797000	usd
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CY2023Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	879529000	usd
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CY2022Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	146285000	usd
CY2023Q4	us-gaap	Business Combination Contingent Consideration Liability Noncurrent BusinessCombinationContingentConsiderationLiabilityNoncurrent	22314000	usd
CY2022Q4	us-gaap	Business Combination Contingent Consideration Liability Noncurrent BusinessCombinationContingentConsiderationLiabilityNoncurrent	36769000	usd
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CY2022Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	79157000	usd
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CY2022Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	2000000	shares
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CY2022Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	52981000	shares
CY2022Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	52981000	shares
CY2023Q4	us-gaap	Common Stock Value CommonStockValue	532000	usd
CY2022Q4	us-gaap	Common Stock Value CommonStockValue	530000	usd
CY2023Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	0	usd
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CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-208144000	usd
CY2023Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1598196000	usd
CY2022Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1390701000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	1403433000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	1183087000	usd
CY2023Q4	us-gaap	Minority Interest MinorityInterest	73000	usd
CY2022Q4	us-gaap	Minority Interest MinorityInterest	50000	usd
CY2023Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1403506000	usd
CY2022Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1183137000	usd
CY2023Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	3820477000	usd
CY2022Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2622776000	usd
CY2023	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	4522550000	usd
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CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	usd
CY2023	us-gaap	Gross Profit GrossProfit	725029000	usd
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CY2021	us-gaap	Gross Profit GrossProfit	498400000	usd
CY2023	ttek	Selling General And Administrative Expenses Including Depreciation And Amortization Of Intangible Assets SellingGeneralAndAdministrativeExpensesIncludingDepreciationAndAmortizationOfIntangibleAssets	305107000	usd
CY2022	ttek	Selling General And Administrative Expenses Including Depreciation And Amortization Of Intangible Assets SellingGeneralAndAdministrativeExpensesIncludingDepreciationAndAmortizationOfIntangibleAssets	234784000	usd
CY2021	ttek	Selling General And Administrative Expenses Including Depreciation And Amortization Of Intangible Assets SellingGeneralAndAdministrativeExpensesIncludingDepreciationAndAmortizationOfIntangibleAssets	222972000	usd
CY2023	ttek	Business Combination Acquisition And Integration Related Expenses BusinessCombinationAcquisitionAndIntegrationRelatedExpenses	33169000	usd
CY2022	ttek	Business Combination Acquisition And Integration Related Expenses BusinessCombinationAcquisitionAndIntegrationRelatedExpenses	0	usd
CY2021	ttek	Business Combination Acquisition And Integration Related Expenses BusinessCombinationAcquisitionAndIntegrationRelatedExpenses	0	usd
CY2023	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	16385000	usd
CY2022	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	0	usd
CY2021	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	0	usd
CY2023	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	-12255000	usd
CY2022	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	-329000	usd
CY2021	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	3273000	usd
CY2023	us-gaap	Operating Income Loss OperatingIncomeLoss	358113000	usd
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CY2023	us-gaap	Investment Income Interest InvestmentIncomeInterest	5898000	usd
CY2022	us-gaap	Investment Income Interest InvestmentIncomeInterest	1780000	usd
CY2021	us-gaap	Investment Income Interest InvestmentIncomeInterest	917000	usd
CY2023	us-gaap	Interest Expense InterestExpense	52435000	usd
CY2022	us-gaap	Interest Expense InterestExpense	13364000	usd
CY2021	us-gaap	Interest Expense InterestExpense	12748000	usd
CY2023	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	89402000	usd
CY2022	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	19904000	usd
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CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	400978000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	348766000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	266870000	usd
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CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.91
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CY2023	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	286269000	usd
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CY2023	us-gaap	Profit Loss ProfitLoss	273452000	usd
CY2022	us-gaap	Profit Loss ProfitLoss	263164000	usd
CY2021	us-gaap	Profit Loss ProfitLoss	232831000	usd
CY2023	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	61206000	usd
CY2022	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	27033000	usd
CY2021	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	23805000	usd
CY2023	us-gaap	Share Based Compensation ShareBasedCompensation	28607000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	26227000	usd
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	23067000	usd
CY2023	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-21204000	usd
CY2022	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	2175000	usd
CY2021	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-38494000	usd
CY2023	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	-12255000	usd
CY2022	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	-329000	usd
CY2021	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	3273000	usd
CY2023	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	16385000	usd
CY2022	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	0	usd
CY2021	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	0	usd
CY2023	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	89402000	usd
CY2022	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	19904000	usd
CY2021	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	0	usd
CY2022	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	14627000	usd
CY2021	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	13090000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-75273000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-56606000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	8740000	usd
CY2023	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	368463000	usd
CY2022	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	336188000	usd
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	304372000	usd
CY2023	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	854319000	usd
CY2022	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	49124000	usd
CY2021	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	84911000	usd
CY2023	us-gaap	Proceeds From Derivative Instrument Investing Activities ProceedsFromDerivativeInstrumentInvestingActivities	109306000	usd
CY2022	us-gaap	Proceeds From Derivative Instrument Investing Activities ProceedsFromDerivativeInstrumentInvestingActivities	0	usd
CY2021	us-gaap	Proceeds From Derivative Instrument Investing Activities ProceedsFromDerivativeInstrumentInvestingActivities	0	usd
CY2023	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	26901000	usd
CY2022	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	10582000	usd
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	8573000	usd
CY2023	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	715000	usd
CY2022	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	3966000	usd
CY2021	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	492000	usd
CY2023	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-771199000	usd
CY2022	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-55740000	usd
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-92992000	usd
CY2023	us-gaap	Proceeds From Issuance Of Secured Debt ProceedsFromIssuanceOfSecuredDebt	994859000	usd
CY2022	us-gaap	Proceeds From Issuance Of Secured Debt ProceedsFromIssuanceOfSecuredDebt	161456000	usd
CY2021	us-gaap	Proceeds From Issuance Of Secured Debt ProceedsFromIssuanceOfSecuredDebt	370222000	usd
CY2023	us-gaap	Repayments Of Secured Debt RepaymentsOfSecuredDebt	1026051000	usd
CY2022	us-gaap	Repayments Of Secured Debt RepaymentsOfSecuredDebt	117080000	usd
CY2021	us-gaap	Repayments Of Secured Debt RepaymentsOfSecuredDebt	414308000	usd
CY2023	us-gaap	Proceeds From Convertible Debt ProceedsFromConvertibleDebt	575000000	usd
CY2022	us-gaap	Proceeds From Convertible Debt ProceedsFromConvertibleDebt	0	usd
CY2021	us-gaap	Proceeds From Convertible Debt ProceedsFromConvertibleDebt	0	usd
CY2023	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	14451000	usd
CY2022	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	0	usd
CY2021	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	0	usd
CY2023	us-gaap	Payments For Derivative Instrument Financing Activities PaymentsForDerivativeInstrumentFinancingActivities	51750000	usd
CY2022	us-gaap	Payments For Derivative Instrument Financing Activities PaymentsForDerivativeInstrumentFinancingActivities	0	usd
CY2021	us-gaap	Payments For Derivative Instrument Financing Activities PaymentsForDerivativeInstrumentFinancingActivities	0	usd
CY2023	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	usd
CY2022	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	200000000	usd
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	60000000	usd
CY2023	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	16833000	usd
CY2022	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	25223000	usd
CY2021	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	17630000	usd
CY2023	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	21328000	usd
CY2022	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	20124000	usd
CY2021	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	20251000	usd
CY2023	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	626000	usd
CY2022	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	1806000	usd
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	11250000	usd
CY2023	us-gaap	Increase Decrease In Book Overdrafts IncreaseDecreaseInBookOverdrafts	0	usd
CY2022	us-gaap	Increase Decrease In Book Overdrafts IncreaseDecreaseInBookOverdrafts	0	usd
CY2021	us-gaap	Increase Decrease In Book Overdrafts IncreaseDecreaseInBookOverdrafts	-36627000	usd
CY2021	us-gaap	Profit Loss ProfitLoss	232831000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	30644000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	6117000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	269592000	usd
CY2021	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	25000	usd
CY2021	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.74
CY2021	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	40041000	usd
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	23067000	usd
CY2021	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-17630000	usd
CY2021	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	11250000	usd
CY2021	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	10705000	usd
CY2021	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	60000000	usd
CY2021Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1234291000	usd
CY2022	us-gaap	Profit Loss ProfitLoss	263164000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-94933000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	11806000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	180037000	usd
CY2022	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	31000	usd
CY2022	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.86
CY2022	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	46099000	usd
CY2022	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	26227000	usd
CY2022	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-25223000	usd
CY2022	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	1806000	usd
CY2022	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	12129000	usd
CY2022	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	200000000	usd
CY2022Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1183137000	usd
CY2023	us-gaap	Profit Loss ProfitLoss	273452000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	12622000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-2638000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-2412000	usd
CY2023	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	286300000	usd
CY2023	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	8000	usd
CY2023	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.98
CY2023	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	52113000	usd
CY2023	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	28607000	usd
CY2023	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-16833000	usd
CY2023	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	626000	usd
CY2023	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	12628000	usd
CY2023	us-gaap	Adjustments To Additional Paid In Capital Other AdjustmentsToAdditionalPaidInCapitalOther	0	usd
CY2023	us-gaap	Adjustments To Additional Paid In Capital Equity Component Of Convertible Debt AdjustmentsToAdditionalPaidInCapitalEquityComponentOfConvertibleDebt	-38838000	usd
CY2023Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1403506000	usd
CY2023	us-gaap	Nature Of Operations NatureOfOperations	Description of Business <div style="margin-bottom:6pt;margin-top:6pt;text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We are a leading global provider of high-end consulting and engineering services that focuses on water, environment, sustainable infrastructure, renewable energy and international development. We are a global company that is </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Leading with Science® </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">to provide innovative solutions for our public and private clients. We typically begin at the earliest stage of a project by identifying technical solutions and developing execution plans tailored to our clients’ needs and resources. </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Our solutions may span the entire life cycle of high-end consulting and engineering projects and include applied science, data analysis, research, engineering, design, project management and operations and maintenance.</span></div><div style="margin-bottom:6pt;margin-top:6pt;text-align:justify;text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We manage our business under two reportable segments. Our Government Services Group (“GSG”) reportable segment primarily includes activities with U.S. government clients (federal, state and local) and all activities with development agencies worldwide. Our Commercial/International Services Group (“CIG”) reportable segment primarily includes activities with U.S. commercial clients and international clients other than development agencies.</span></div>
CY2023	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2023	us-gaap	Fiscal Period FiscalPeriod	<span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Fiscal Year. </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We report results of operations based on 52 or 53-week periods ending on the Sunday nearest September 3</span>0. Fiscal years 2023, 2022 and 2021 contained 52, 52 and 53 weeks, respectively.
CY2023	us-gaap	Use Of Estimates UseOfEstimates	<span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates.</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") requires us to make estimates and assumptions. These estimates and assumptions affect the amounts reported in our consolidated financial statements and accompanying notes. Although such estimates and assumptions are based on management's best knowledge of current events and actions we may take in the future, actual results could differ materially from those estimates.</span>
CY2023	ttek	Maximum Term Of Original Maturity To Classify An Instrument As Cash Equivalent MaximumTermOfOriginalMaturityToClassifyAnInstrumentAsCashEquivalent	P90D
CY2023	ttek	Revenue Remaining Performance Obligation Termination Notice Period Three RevenueRemainingPerformanceObligationTerminationNoticePeriodThree	P90D
CY2023	ttek	Unbilled Contracts Receivable Period For Billing And Collection UnbilledContractsReceivablePeriodForBillingAndCollection	P12M
CY2023	ttek	Number Of Levels Below Segments For Goodwill Impairment Testing NumberOfLevelsBelowSegmentsForGoodwillImpairmentTesting	1	level
CY2023	ttek	Number Of Levels Below Segments For Goodwill Impairment Testing NumberOfLevelsBelowSegmentsForGoodwillImpairmentTesting	1	level
CY2021	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	479369	shares
CY2021	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	125.16
CY2021	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	60000000	usd
CY2023	ttek	Concentration Of Credit Risk Number Of Financial Institutions For Investment Exposure ConcentrationOfCreditRiskNumberOfFinancialInstitutionsForInvestmentExposure	1	institution
CY2023Q4	ttek	Percentage Of Account Receivables Due From Agencies PercentageOfAccountReceivablesDueFromAgencies	0.22
CY2023Q4	us-gaap	Government Assistance Amount Cumulative Current GovernmentAssistanceAmountCumulativeCurrent	21000000	usd
CY2023Q4	ttek	Government Assistance Amount Expected To Be Recognized In Next Twelve Months GovernmentAssistanceAmountExpectedToBeRecognizedInNextTwelveMonths	10000000	usd
CY2023Q4	us-gaap	Government Assistance Amount Cumulative Noncurrent GovernmentAssistanceAmountCumulativeNoncurrent	11000000	usd
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3504048000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	usd
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3504048000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	usd
CY2023Q4	us-gaap	Contract With Customer Asset Net Current ContractWithCustomerAssetNetCurrent	113939000	usd
CY2022Q4	us-gaap	Contract With Customer Asset Net Current ContractWithCustomerAssetNetCurrent	92405000	usd
CY2023Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	335044000	usd
CY2022Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	241340000	usd
CY2023Q4	ttek	Contract With Customer Asset Liability Net Current ContractWithCustomerAssetLiabilityNetCurrent	-221105000	usd
CY2022Q4	ttek	Contract With Customer Asset Liability Net Current ContractWithCustomerAssetLiabilityNetCurrent	-148935000	usd
CY2023	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	164000000	usd
CY2022	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	125000000	usd
CY2023	us-gaap	Contract With Customer Liability Cumulative Catch Up Adjustment To Revenue Change In Measure Of Progress ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress	11000000	usd
CY2022Q4	us-gaap	Provision For Loss On Contracts ProvisionForLossOnContracts	10000000	usd
CY2022Q4	ttek	Revenue Recognition Estimated Cost To Complete Related Contracts RevenueRecognitionEstimatedCostToCompleteRelatedContracts	80000000	usd
CY2022Q4	us-gaap	Billed Contract Receivables BilledContractReceivables	491700000	usd
CY2022Q4	us-gaap	Unbilled Contracts Receivable UnbilledContractsReceivable	267161000	usd
CY2022Q4	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	758861000	usd
CY2022Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	3749000	usd
CY2022Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	755112000	usd
CY2023	ttek	Unbilled Contracts Receivable Period For Billing And Collection UnbilledContractsReceivablePeriodForBillingAndCollection	P12M
CY2023Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	4800000000	usd
CY2023Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	4755077000	usd
CY2023	ttek	Revenue Remaining Performance Obligation Termination Notice Period One RevenueRemainingPerformanceObligationTerminationNoticePeriodOne	P30D
CY2023	ttek	Revenue Remaining Performance Obligation Termination Notice Period Two RevenueRemainingPerformanceObligationTerminationNoticePeriodTwo	P60Y
CY2022Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.23
CY2022Q4	us-gaap	Dividends Dividends	12186000	usd
CY2023Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.23
CY2023Q1	us-gaap	Dividends Dividends	12242000	usd
CY2023Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.26
CY2023Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.26
CY2023	us-gaap	Dividends Dividends	52113000	usd
CY2021Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.20
CY2021Q4	us-gaap	Dividends Dividends	10793000	usd
CY2022Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.20
CY2022Q1	us-gaap	Dividends Dividends	10769000	usd
CY2022Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.23
CY2022Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.23
CY2022	us-gaap	Dividends Dividends	46099000	usd
CY2020Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.17
CY2020Q4	us-gaap	Dividends Dividends	9198000	usd
CY2021Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.17
CY2021Q1	us-gaap	Dividends Dividends	9212000	usd
CY2021Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.20
CY2021Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.20
CY2021Q3	us-gaap	Dividends Dividends	10800000	usd
CY2021	us-gaap	Dividends Dividends	40041000	usd
CY2022	us-gaap	Number Of Businesses Acquired NumberOfBusinessesAcquired	4	acquisition
CY2023	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	-12300000	usd
CY2021	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	3300000	usd
CY2023Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	73400000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11500000	usd
CY2023	us-gaap	Finite Lived Intangible Assets Translation And Purchase Accounting Adjustments FiniteLivedIntangibleAssetsTranslationAndPurchaseAccountingAdjustments	-200000	usd
CY2022	us-gaap	Finite Lived Intangible Assets Translation And Purchase Accounting Adjustments FiniteLivedIntangibleAssetsTranslationAndPurchaseAccountingAdjustments	-5300000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	113683000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	86338000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	55648000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	1108578000	usd
CY2022	us-gaap	Goodwill Transfers GoodwillTransfers	0	usd
CY2023	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	759876000	usd
CY2023	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	9956000	usd
CY2023Q4	us-gaap	Goodwill Goodwill	1880244000	usd
CY2023Q3	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2023Q3	us-gaap	Reporting Unit Percentage Of Fair Value In Excess Of Carrying Amount ReportingUnitPercentageOfFairValueInExcessOfCarryingAmount	0.45
CY2023Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	270453000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	96517000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	173936000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	87673000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	58510000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	29163000	usd
CY2023	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	41200000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	13200000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	42180000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	28032000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	19922000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	13861000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	13352000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	56589000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	173936000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	177477000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	129138000	usd
CY2023Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	102645000	usd
CY2022Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	96822000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	74832000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	32316000	usd
CY2023	us-gaap	Depreciation Depreciation	20000000	usd
CY2022	us-gaap	Depreciation Depreciation	13900000	usd
CY2021	us-gaap	Depreciation Depreciation	12300000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	287295000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	262428000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	211222000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	400978000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	348766000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	266870000	usd
CY2023	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	110371000	usd
CY2022	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	47447000	usd
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	41056000	usd
CY2023	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	16025000	usd
CY2022	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	9613000	usd
CY2021	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	9893000	usd
CY2023	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	28970000	usd
CY2022	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	26332000	usd
CY2021	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	18887000	usd
CY2023	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	155366000	usd
CY2022	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	83392000	usd
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	69836000	usd
CY2023	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-18062000	usd
CY2022	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-424000	usd
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-6034000	usd
CY2023	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-4976000	usd
CY2022	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-382000	usd
CY2021	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-2060000	usd
CY2023	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-4802000	usd
CY2022	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	3016000	usd
CY2021	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-27703000	usd
CY2023	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-27840000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	2210000	usd
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-35797000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	127526000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	85602000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	34039000	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.001
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.010
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.009
CY2023	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.318
CY2022	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.245
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.128
CY2023	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.318
CY2022	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.245
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.128
CY2023	ttek	Income Tax Expense Benefit Nonoperating IncomeTaxExpenseBenefitNonoperating	20600000	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-4600000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-10300000	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2022	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2021	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2023	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.022
CY2022	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.021
CY2021	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.023
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.005
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.010
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.026
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.015
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.010
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.009
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.010
CY2023	ttek	Effective Income Tax Rate Reconciliation Sharebased Payment Arrangement Percent EffectiveIncomeTaxRateReconciliationSharebasedPaymentArrangementPercent	-0.004
CY2022	ttek	Effective Income Tax Rate Reconciliation Sharebased Payment Arrangement Percent EffectiveIncomeTaxRateReconciliationSharebasedPaymentArrangementPercent	-0.020
CY2021	ttek	Effective Income Tax Rate Reconciliation Sharebased Payment Arrangement Percent EffectiveIncomeTaxRateReconciliationSharebasedPaymentArrangementPercent	-0.033
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.002
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.093
CY2023	ttek	Effective Income Tax Rate Reconciliation Change In Uncertain Tax Positions Percent EffectiveIncomeTaxRateReconciliationChangeInUncertainTaxPositionsPercent	0.116
CY2022	ttek	Effective Income Tax Rate Reconciliation Change In Uncertain Tax Positions Percent EffectiveIncomeTaxRateReconciliationChangeInUncertainTaxPositionsPercent	-0.011
CY2021	ttek	Effective Income Tax Rate Reconciliation Change In Uncertain Tax Positions Percent EffectiveIncomeTaxRateReconciliationChangeInUncertainTaxPositionsPercent	0.017
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	0.011
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	0.014
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	-0.037
CY2023	ttek	Effective Income Tax Rate Reconciliation Nondeductible Expense Employee Compensation Percent EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEmployeeCompensationPercent	0.012
CY2022	ttek	Effective Income Tax Rate Reconciliation Nondeductible Expense Employee Compensation Percent EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEmployeeCompensationPercent	0.019
CY2021	ttek	Effective Income Tax Rate Reconciliation Nondeductible Expense Employee Compensation Percent EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEmployeeCompensationPercent	0.020
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Repatriation Of Foreign Earnings EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings	0
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Repatriation Of Foreign Earnings EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings	0.001
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Repatriation Of Foreign Earnings EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings	0.021
CY2023	ttek	Effective Income Tax Rate Reconciliation Unremitted Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationUnremittedForeignEarningsPercent	0.002
CY2022	ttek	Effective Income Tax Rate Reconciliation Unremitted Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationUnremittedForeignEarningsPercent	-0.002
CY2021	ttek	Effective Income Tax Rate Reconciliation Unremitted Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationUnremittedForeignEarningsPercent	0.010
CY2023	ttek	Effective Income Tax Reconciliation Hedging Gain Loss EffectiveIncomeTaxReconciliationHedgingGainLoss	-0.057
CY2022	ttek	Effective Income Tax Reconciliation Hedging Gain Loss EffectiveIncomeTaxReconciliationHedgingGainLoss	0
CY2021	ttek	Effective Income Tax Reconciliation Hedging Gain Loss EffectiveIncomeTaxReconciliationHedgingGainLoss	0
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Gilti Percent EffectiveIncomeTaxRateReconciliationGiltiPercent	0.005
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Gilti Percent EffectiveIncomeTaxRateReconciliationGiltiPercent	0
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Gilti Percent EffectiveIncomeTaxRateReconciliationGiltiPercent	0
CY2023	ttek	Effective Income Tax Rate Reconciliation Other Non Recurring Adjustments To Deferred Taxes Percent EffectiveIncomeTaxRateReconciliationOtherNonRecurringAdjustmentsToDeferredTaxesPercent	-0.010
CY2022	ttek	Effective Income Tax Rate Reconciliation Other Non Recurring Adjustments To Deferred Taxes Percent EffectiveIncomeTaxRateReconciliationOtherNonRecurringAdjustmentsToDeferredTaxesPercent	0.001
CY2021	ttek	Effective Income Tax Rate Reconciliation Other Non Recurring Adjustments To Deferred Taxes Percent EffectiveIncomeTaxRateReconciliationOtherNonRecurringAdjustmentsToDeferredTaxesPercent	0.008
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-12900000	usd
CY2023	ttek	Effective Income Tax Rate Reconciliation Excluding Valuation Allowance Release Non Deductible Goodwill Impairment Transaction Costs And Excess Tax Benefits On Share Based Payments Percent EffectiveIncomeTaxRateReconciliationExcludingValuationAllowanceReleaseNonDeductibleGoodwillImpairmentTransactionCostsAndExcessTaxBenefitsOnShareBasedPaymentsPercent	0.278
CY2022	ttek	Effective Income Tax Rate Reconciliation Excluding Valuation Allowance Release Non Deductible Goodwill Impairment Transaction Costs And Excess Tax Benefits On Share Based Payments Percent EffectiveIncomeTaxRateReconciliationExcludingValuationAllowanceReleaseNonDeductibleGoodwillImpairmentTransactionCostsAndExcessTaxBenefitsOnShareBasedPaymentsPercent	0.275
CY2021	ttek	Effective Income Tax Rate Reconciliation Excluding Valuation Allowance Release Non Deductible Goodwill Impairment Transaction Costs And Excess Tax Benefits On Share Based Payments Percent EffectiveIncomeTaxRateReconciliationExcludingValuationAllowanceReleaseNonDeductibleGoodwillImpairmentTransactionCostsAndExcessTaxBenefitsOnShareBasedPaymentsPercent	0.257
CY2023Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	2686000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	1238000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	2849000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	5023000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	5323000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	4986000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	64155000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	35973000	usd
CY2023Q4	ttek	Deferred Tax Assets Leasing Arrangements DeferredTaxAssetsLeasingArrangements	53437000	usd
CY2022Q4	ttek	Deferred Tax Assets Leasing Arrangements DeferredTaxAssetsLeasingArrangements	49618000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	1900000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	2925000	usd
CY2023Q4	ttek	Deferred Tax Assets Unbilled Revenue DeferredTaxAssetsUnbilledRevenue	3090000	usd
CY2022Q4	ttek	Deferred Tax Assets Unbilled Revenue DeferredTaxAssetsUnbilledRevenue	4885000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	62777000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	41648000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	552000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	0	usd
CY2023Q4	ttek	Deferred Tax Assets Capitalized Research And Development DeferredTaxAssetsCapitalizedResearchAndDevelopment	17778000	usd
CY2022Q4	ttek	Deferred Tax Assets Capitalized Research And Development DeferredTaxAssetsCapitalizedResearchAndDevelopment	0	usd
CY2023Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	12696000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	0	usd
CY2023Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	11663000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	12286000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	215580000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	134010000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	2703000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	6065000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	53437000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	49618000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	83242000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	42863000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	1453000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	2200000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	0	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	621000	usd
CY2023Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	140835000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	101367000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	74745000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	32643000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	11700000	usd
CY2023Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	53600000	usd
CY2022Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	246250000	usd
CY2021	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	18157000	usd
CY2023Q4	ttek	Defined Benefit Plan Pension Plan Open For New Entrants Maximum Age DefinedBenefitPlanPensionPlanOpenForNewEntrantsMaximumAge	P24Y
CY2023Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	107377000	usd
CY2023Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	116706000	usd
CY2023	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	6012000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	0	usd
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	0	usd
CY2023	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	27272000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	usd
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	2171000	usd
CY2023	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	14602000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	usd
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	1500000	usd
CY2023	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	1358000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	3014000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	0	usd
CY2023	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	1817000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	977000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	usd
CY2023Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	53619000	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	8908000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	12899000	usd
CY2023	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	4600000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	500000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	800000	usd
CY2023	us-gaap	Tax Adjustments Settlements And Unusual Provisions TaxAdjustmentsSettlementsAndUnusualProvisions	-2000000	usd
CY2022	us-gaap	Tax Adjustments Settlements And Unusual Provisions TaxAdjustmentsSettlementsAndUnusualProvisions	-400000	usd
CY2021	us-gaap	Tax Adjustments Settlements And Unusual Provisions TaxAdjustmentsSettlementsAndUnusualProvisions	0	usd
CY2023Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	8000000	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	5300000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	5200000	usd
CY2023Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	15471000	usd
CY2022Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	0	usd
CY2023Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	0	usd
CY2022Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	12504000	usd
CY2023Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	879529000	usd
CY2023Q3	ttek	Derivative Cap Price Per Share DerivativeCapPricePerShare	259.56
CY2023Q3	ttek	Cap Price Premium Over Reported Sales Price Percentage CapPricePremiumOverReportedSalesPricePercentage	0.65
CY2023Q3	ttek	Common Stock Reported Sales Price CommonStockReportedSalesPrice	157.31
CY2023Q4	us-gaap	Bank Overdrafts BankOverdrafts	0	usd
CY2023Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	320000000	usd
CY2023Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	575000000	usd
CY2023Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	895000000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Renewal Term LesseeOperatingLeaseRenewalTerm	P5Y
CY2023	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	16400000	usd
CY2023	us-gaap	Operating Lease Cost OperatingLeaseCost	93674000	usd
CY2022	us-gaap	Operating Lease Cost OperatingLeaseCost	86725000	usd
CY2023	us-gaap	Sublease Income SubleaseIncome	740000	usd
CY2022	us-gaap	Sublease Income SubleaseIncome	150000	usd
CY2023	us-gaap	Lease Cost LeaseCost	92934000	usd
CY2022	us-gaap	Lease Cost LeaseCost	86575000	usd
CY2023	us-gaap	Operating Lease Payments OperatingLeasePayments	78268000	usd
CY2022	us-gaap	Operating Lease Payments OperatingLeasePayments	71365000	usd
CY2023	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	70552000	usd
CY2022	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	44096000	usd
CY2021	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4910000	usd
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	175932000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	182319000	usd
CY2023Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	65005000	usd
CY2022Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	57865000	usd
CY2023Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	144685000	usd
CY2022Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	146285000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	209690000	usd
CY2022Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	204150000	usd
CY2023Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y
CY2022Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y
CY2023Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.030
CY2022Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.022
CY2023Q4	ttek	Lessee Operating Lease Lease Not Yet Commenced Undiscounted Amount LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedAmount	8300000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	69562000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	53685000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	36013000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	24904000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	16545000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	25671000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	226380000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	16690000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	209690000	usd
CY2021	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	23067000	usd
CY2022Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	168000	shares
CY2022Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	38.62
CY2023	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	20000	shares
CY2023	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	32.30
CY2023	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	0	shares
CY2023	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	0
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	148000	shares
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	39.45
CY2023	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y2M12D
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	16708000	usd
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber	148000	shares
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice	39.45
CY2023	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P3Y2M12D
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue	16708000	usd
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	148000	shares
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	39.45
CY2023	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P3Y2M12D
CY2023Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	16708000	usd
CY2023	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2022	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2023	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	31600000	usd
CY2022	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	29300000	usd
CY2021	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	26900000	usd
CY2023Q4	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	43500000	usd
CY2022Q4	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	36700000	usd
CY2023Q4	us-gaap	Deferred Compensation Liability Classified Noncurrent DeferredCompensationLiabilityClassifiedNoncurrent	43400000	usd
CY2022Q4	us-gaap	Deferred Compensation Liability Classified Noncurrent DeferredCompensationLiabilityClassifiedNoncurrent	36300000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	39572000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	36250000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	35303000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	33006000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	4269000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	3244000	usd
CY2023	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	1300000	usd
CY2022	us-gaap	Defined Benefit Plan Benefit Obligation Benefits Paid DefinedBenefitPlanBenefitObligationBenefitsPaid	1000000	usd
CY2023Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	39572000	usd
CY2022Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	36250000	usd
CY2022Q4	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGain	19900000	usd
CY2023Q1	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGain	68000000	usd
CY2023Q2	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGain	21400000	usd
CY2023Q4	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	16400000	usd
CY2023Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	894766000	usd
CY2023Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1158226000	usd
CY2023Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1208947000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	263125000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	263125000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	232810000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	232810000	usd
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53620000	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54078000	shares
CY2022	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	543000	shares
CY2021	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	597000	shares
CY2023	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53637000	shares
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.14
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.10
CY2022	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2023	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2021	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-2400000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	11800000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	6100000	usd
CY2023Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1260611000	usd
CY2023Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	92050000	usd
CY2023Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	61011000	usd
CY2023Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	97675000	usd
CY2019Q3	ttek	Loss Contingency Number Of Actions LossContingencyNumberOfActions	3	action
CY2023	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2023	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	16400000	usd
CY2023	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	4522550000	usd
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3504048000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	usd
CY2023	us-gaap	Operating Income Loss OperatingIncomeLoss	358113000	usd
CY2022	us-gaap	Operating Income Loss OperatingIncomeLoss	340446000	usd
CY2021	us-gaap	Operating Income Loss OperatingIncomeLoss	278701000	usd
CY2023	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	41200000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	13200000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11500000	usd
CY2023	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	-12300000	usd
CY2022	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	-300000	usd
CY2021	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	3300000	usd
CY2023Q4	us-gaap	Assets Assets	3820477000	usd
CY2022Q4	us-gaap	Assets Assets	2622776000	usd
CY2023	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	4522550000	usd
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3504048000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	usd
CY2023Q4	us-gaap	Noncurrent Assets NoncurrentAssets	320030000	usd
CY2022Q4	us-gaap	Noncurrent Assets NoncurrentAssets	277180000	usd
CY2023	us-gaap	Related Party Transaction Amounts Of Transaction RelatedPartyTransactionAmountsOfTransaction	78500000	usd
CY2022	us-gaap	Related Party Transaction Amounts Of Transaction RelatedPartyTransactionAmountsOfTransaction	91700000	usd
CY2021	us-gaap	Related Party Transaction Amounts Of Transaction RelatedPartyTransactionAmountsOfTransaction	92400000	usd
CY2023Q1	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	116706000	usd
CY2023Q2	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	42830000	usd
CY2023Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	42830000	usd
CY2023Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	60235000	usd
CY2023Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	60235000	usd
CY2023Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	53649000	usd
CY2023Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.20
CY2023Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.80
CY2023Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.13
CY2023Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.01
CY2023Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.18
CY2023Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.80
CY2023Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.12
CY2023Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.00
CY2023Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53069000	shares
CY2023Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53227000	shares
CY2023Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53231000	shares
CY2023Q4	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53247000	shares
CY2023Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53529000	shares
CY2023Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53627000	shares
CY2023Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53653000	shares
CY2023Q4	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53702000	shares
CY2022Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	858510000	usd
CY2022Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	852744000	usd
CY2022Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	890231000	usd
CY2022Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	902562000	usd
CY2022Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	87220000	usd
CY2022Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	74520000	usd
CY2022Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	83905000	usd
CY2022Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	94802000	usd
CY2022Q1	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	68489000	usd
CY2022Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	68489000	usd
CY2022Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	53040000	usd
CY2022Q2	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	53040000	usd
CY2022Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	58650000	usd
CY2022Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	58650000	usd
CY2022Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	82947000	usd
CY2022Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.27
CY2022Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.99
CY2022Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.10
CY2022Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.56
CY2022Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.25
CY2022Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.98
CY2022Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.09
CY2022Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.55
CY2022Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53937000	shares
CY2022Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53834000	shares
CY2022Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53507000	shares
CY2022Q4	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53148000	shares
CY2022Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54577000	shares
CY2022Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54346000	shares
CY2022Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54006000	shares
CY2022Q4	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53667000	shares
CY2022	dei	Auditor Firm AuditorFirmId	238
CY2023	dei	Auditor Firm AuditorFirmId	238

Files In Submission

Name	View Source	Status
0000831641-23-000082-index-headers.html	Edgar Link	pending
0000831641-23-000082-index.html	Edgar Link	pending
0000831641-23-000082.txt	Edgar Link	pending
0000831641-23-000082-xbrl.zip	Edgar Link	pending
Financial_Report.xlsx	Edgar Link	pending
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$TTEK
TETRA TECH INC Stock $ttek

2023 Q4 Form 10-K Financial Statement

#000083164123000082 Filed on November 22, 2023

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

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$TTEK TETRA TECH INC Stock $ttek

2023 Q4 Form 10-K Financial Statement

#000083164123000082 Filed on November 22, 2023

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$TTEK
TETRA TECH INC Stock $ttek