$TTEK
TETRA TECH INC Stock $ttek

$ttek Overview Financials Valuation SEC Filings Company Website

2021 Q4 Form 10-K Financial Statement

#000083164121000110 Filed on November 24, 2021

Income Statement

Concept	2021 Q4	2021	2020 Q3
Revenue	$709.1M	$3.214B	$753.4M
YoY Change	-7.32%	7.3%	-10.47%
Cost Of Revenue	$565.2M	$2.054B	$464.4M
YoY Change	15.61%	7.98%	-12.82%
Gross Profit	$143.9M	$498.4M	$125.4M
YoY Change	23.73%	11.61%	32.0%
Gross Profit Margin	20.29%	15.51%	16.65%
Selling, General & Admin	$65.18M	$223.0M	$56.30M
YoY Change	30.11%	8.98%	1.99%
% of Gross Profit	45.29%	44.74%	44.9%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$6.994M	$23.81M	$5.500M
YoY Change	12.12%	-3.27%	-26.67%
% of Gross Profit	4.86%	4.78%	4.39%
Operating Expenses	$62.07M	$219.7M	$42.90M
YoY Change	24.15%	15.81%	-23.67%
Operating Profit	$81.84M	$278.7M	$66.74M
YoY Change	23.52%	15.6%	222.94%
Interest Expense	-$3.246M	$12.75M	-$2.700M
YoY Change	8.2%	-11.93%	-32.5%
% of Operating Profit	-3.97%	4.57%	-4.05%
Other Income/Expense, Net		$0.00
YoY Change
Pretax Income	$78.59M	$266.9M	$64.00M
YoY Change	24.3%	17.05%	285.54%
Income Tax	-$4.341M	$34.04M	$19.40M
% Of Pretax Income	-5.52%	12.75%	30.31%
Net Earnings	$82.95M	$232.8M	$44.70M
YoY Change	58.16%	33.9%	288.7%
Net Earnings / Revenue	11.7%	7.25%	5.93%
Basic Earnings Per Share		$4.31	$0.83
Diluted Earnings Per Share	$1.519M	$4.26	$0.82
COMMON SHARES
Basic Shares Outstanding	53.89M shares	54.08M shares	53.84M shares
Diluted Shares Outstanding		54.68M shares	54.60M shares

Balance Sheet

Concept	2021 Q4	2021	2020 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$166.6M	$166.6M	$157.5M
YoY Change	1.94%	5.76%	30.49%
Cash & Equivalents	$166.6M	$166.6M	$157.5M
Short-Term Investments
Other Short-Term Assets	$112.3M	$112.3M	$81.10M
YoY Change	22.64%	38.52%	30.39%
Inventory
Prepaid Expenses
Receivables	$669.0M	$772.8M	$649.0M
Other Receivables	$14.26M	$14.26M	$19.50M
Total Short-Term Assets	$1.066B	$1.066B	$999.8M
YoY Change	2.95%	6.62%	-7.41%
LONG-TERM ASSETS
Property, Plant & Equipment	$37.73M	$253.2M	$35.51M
YoY Change	7.38%	-7.91%	-9.97%
Goodwill	$1.109B		$993.5M
YoY Change	8.91%		7.43%
Intangibles
YoY Change
Long-Term Investments	$3.282M	$3.282M	$7.332M
YoY Change	-58.56%	-55.04%	6.68%
Other Assets	$53.20M	$107.6M	$57.05M
YoY Change	12.55%	20.77%	10.43%
Total Long-Term Assets	$1.511B	$1.511B	$1.379B
YoY Change	9.51%	9.56%	29.15%
TOTAL ASSETS
Total Short-Term Assets	$1.066B	$1.066B	$999.8M
Total Long-Term Assets	$1.511B	$1.511B	$1.379B
Total Assets	$2.577B	$2.577B	$2.379B
YoY Change	6.7%	8.32%	10.76%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$128.8M	$128.8M	$111.8M
YoY Change	-4.92%	15.18%	-45.89%
Accrued Expenses	$273.8M	$273.8M	$269.5M
YoY Change	31.81%	1.59%	32.5%
Deferred Revenue	$190.4M		$171.9M
YoY Change	-4.46%		3.8%
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$12.50M	$12.50M	$49.26M
YoY Change	-52.29%	-74.64%	290.98%
Total Short-Term Liabilities	$848.5M	$848.5M	$793.5M
YoY Change	12.42%	6.93%	3.05%
LONG-TERM LIABILITIES
Long-Term Debt	$200.0M	$200.0M	$242.4M
YoY Change	-27.53%	-17.49%	-8.16%
Other Long-Term Liabilities	$69.16M	$283.2M	$80.59M
YoY Change	8.23%	-2.0%	-2.99%
Total Long-Term Liabilities	$269.2M	$483.2M	$323.0M
YoY Change	-20.81%	-9.07%	-6.92%
TOTAL LIABILITIES
Total Short-Term Liabilities	$848.5M	$848.5M	$793.5M
Total Long-Term Liabilities	$269.2M	$483.2M	$323.0M
Total Liabilities	$1.118B	$1.342B	$1.116B
YoY Change	2.1%	0.08%	-0.05%
SHAREHOLDERS EQUITY
Retained Earnings	$1.359B		$1.199B
YoY Change	10.24%		11.89%
Common Stock	$540.0K		$538.0K
YoY Change	-0.37%		-99.32%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$1.234B	$1.234B	$1.037B
YoY Change
Total Liabilities & Shareholders Equity	$2.577B	$2.577B	$2.379B
YoY Change	6.7%	8.32%	10.76%

Cashflow Statement

Concept	2021 Q4	2021	2020 Q3
OPERATING ACTIVITIES
Net Income	$82.95M	$232.8M	$44.70M
YoY Change	58.16%	33.9%	288.7%
Depreciation, Depletion And Amortization	$6.994M	$23.81M	$5.500M
YoY Change	12.12%	-3.27%	-26.67%
Cash From Operating Activities	$77.83M	$304.4M	$67.90M
YoY Change	134.58%	15.96%	-28.6%
INVESTING ACTIVITIES
Capital Expenditures	-$2.339M	$8.573M	-$2.800M
YoY Change	-230.31%	-29.99%	-54.84%
Acquisitions		$84.91M
YoY Change		23.98%
Other Investing Activities	-$67.60M	-$84.42M	-$39.50M
YoY Change		66.18%	-19.06%
Cash From Investing Activities	-$69.94M	-$92.99M	-$42.30M
YoY Change	3815.85%	47.55%	-23.09%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$60.00M
YoY Change		-48.8%
Debt Paid & Issued, Net		$414.3M
YoY Change		25.14%
Cash From Financing Activities	-72.60M	-$210.1M	-10.40M
YoY Change	121.14%	28.86%	-88.15%
NET CHANGE
Cash From Operating Activities	77.83M	$304.4M	67.90M
Cash From Investing Activities	-69.94M	-$92.99M	-42.30M
Cash From Financing Activities	-72.60M	-$210.1M	-10.40M
Net Change In Cash	-64.70M	$9.053M	15.20M
YoY Change	-1192.32%	-75.27%	-131.87%
FREE CASH FLOW
Cash From Operating Activities	$77.83M	$304.4M	$67.90M
Capital Expenditures	-$2.339M	$8.573M	-$2.800M
Free Cash Flow	$80.17M	$295.8M	$70.70M
YoY Change	155.45%	18.21%	-30.21%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2021	dei	Document Annual Report DocumentAnnualReport	true
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1
CY2021	dei	Document Type DocumentType	10-K
CY2021	dei	Entity Central Index Key EntityCentralIndexKey	0000831641
CY2021	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
CY2021	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2021	dei	Amendment Flag AmendmentFlag	false
CY2021	dei	Document Period End Date DocumentPeriodEndDate	2021-10-03
CY2021	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--10-03
CY2021	dei	Document Transition Report DocumentTransitionReport	false
CY2021	dei	Entity File Number EntityFileNumber	0-19655
CY2021	dei	Entity Registrant Name EntityRegistrantName	TETRA TECH, INC.
CY2021	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2021	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	95-4148514
CY2021	dei	Entity Address Address Line1 EntityAddressAddressLine1	3475 East Foothill Boulevard
CY2021	dei	Entity Address City Or Town EntityAddressCityOrTown	Pasadena
CY2021	dei	Entity Address State Or Province EntityAddressStateOrProvince	CA
CY2021	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	91107
CY2021	dei	City Area Code CityAreaCode	626
CY2021	dei	Local Phone Number LocalPhoneNumber	351-4664
CY2021	dei	Security12b Title Security12bTitle	Common Stock, $0.01 par value
CY2021	dei	Trading Symbol TradingSymbol	TTEK
CY2021	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2021	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2021	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2021	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2021	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2021	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2021	dei	Entity Small Business EntitySmallBusiness	false
CY2021	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2021	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	37733000	USD
CY2021	dei	Entity Shell Company EntityShellCompany	false
CY2021Q1	dei	Entity Public Float EntityPublicFloat	7100000000	USD
CY2021Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	53885546	shares
CY2021Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	166568000	USD
CY2020Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	157515000	USD
CY2021Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	668998000	USD
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CY2021Q4	us-gaap	Contract With Customer Asset Net Current ContractWithCustomerAssetNetCurrent	103784000	USD
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CY2021Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	14260000	USD
CY2020Q3	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	19509000	USD
CY2021Q4	us-gaap	Assets Current AssetsCurrent	1065948000	USD
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CY2020Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	35507000	USD
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	215422000	USD
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CY2021Q4	us-gaap	Equity Method Investments EquityMethodInvestments	3282000	USD
CY2020Q3	us-gaap	Equity Method Investments EquityMethodInvestments	7332000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	1108578000	USD
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CY2021Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	54413000	USD
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CY2021Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
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CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-125028000	USD
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CY2021Q4	us-gaap	Minority Interest MinorityInterest	53000	USD
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CY2021Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1234291000	USD
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CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	USD
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CY2021	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	3273000	USD
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CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.31
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CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.89
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.26
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CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54078000	shares
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CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54986000	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54675000	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	55022000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	55936000	shares
CY2021	us-gaap	Profit Loss ProfitLoss	232831000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	173890000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	158761000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	30644000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	3435000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-20866000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	6117000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-4638000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	-12125000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	36761000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-1203000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-32991000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	269592000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	172687000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	125770000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	24000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	30000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	336000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	269568000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	172657000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	125434000	USD
CY2021	us-gaap	Profit Loss ProfitLoss	232831000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	173890000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	158761000	USD
CY2021	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	23805000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	24611000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	28844000	USD
CY2021	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	4990000	USD
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	6605000	USD
CY2019	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	4073000	USD
CY2021	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	4604000	USD
CY2020	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	6310000	USD
CY2019	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	4048000	USD
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	23067000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	19424000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	17618000	USD
CY2021	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-38494000	USD
CY2020	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	565000	USD
CY2019	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-37615000	USD
CY2021	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	-4130000	USD
CY2020	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1267000	USD
CY2019	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	16964000	USD
CY2021	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	15800000	USD
CY2019	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	7755000	USD
CY2021	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	3273000	USD
CY2020	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	14971000	USD
CY2019	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	-1085000	USD
CY2021	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	110000	USD
CY2020	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	11066000	USD
CY2019	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	232000	USD
CY2021	ttek	Increase Decrease In Accounts Receivable And Contract With Customer Asset IncreaseDecreaseInAccountsReceivableAndContractWithCustomerAsset	-17431000	USD
CY2020	ttek	Increase Decrease In Accounts Receivable And Contract With Customer Asset IncreaseDecreaseInAccountsReceivableAndContractWithCustomerAsset	-154748000	USD
CY2019	ttek	Increase Decrease In Accounts Receivable And Contract With Customer Asset IncreaseDecreaseInAccountsReceivableAndContractWithCustomerAsset	10226000	USD
CY2021	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	582000	USD
CY2020	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	11321000	USD
CY2019	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-2568000	USD
CY2021	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	13551000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-102162000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	39011000	USD
CY2021	ttek	Increase Decrease In Accrued Compensation IncreaseDecreaseInAccruedCompensation	5425000	USD
CY2020	ttek	Increase Decrease In Accrued Compensation IncreaseDecreaseInAccruedCompensation	-8173000	USD
CY2019	ttek	Increase Decrease In Accrued Compensation IncreaseDecreaseInAccruedCompensation	18359000	USD
CY2021	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	13407000	USD
CY2020	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	5894000	USD
CY2019	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	-6039000	USD
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	8740000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	19460000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-16929000	USD
CY2021	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	13090000	USD
CY2020	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	-5192000	USD
CY2019	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	-11386000	USD
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	304372000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	262479000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	208513000	USD
CY2021	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	84911000	USD
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	68488000	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	84159000	USD
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	8573000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	12245000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	16198000	USD
CY2021	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	492000	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	17710000	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	651000	USD
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-92992000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-63023000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-99706000	USD
CY2021	us-gaap	Proceeds From Issuance Of Long Term Debt And Capital Securities Net ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet	370222000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt And Capital Securities Net ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet	308364000	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt And Capital Securities Net ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet	417262000	USD
CY2021	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	414308000	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	331066000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	415491000	USD
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	60000000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	117188000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	100000000	USD
CY2021	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	17630000	USD
CY2020	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	11166000	USD
CY2019	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	6893000	USD
CY2021	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	20251000	USD
CY2020	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	22900000	USD
CY2019	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	12018000	USD
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	11250000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	10334000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	11751000	USD
CY2021	us-gaap	Increase Decrease In Book Overdrafts IncreaseDecreaseInBookOverdrafts	-36627000	USD
CY2020	us-gaap	Increase Decrease In Book Overdrafts IncreaseDecreaseInBookOverdrafts	36627000	USD
CY2019	us-gaap	Increase Decrease In Book Overdrafts IncreaseDecreaseInBookOverdrafts	0	USD
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	40041000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	34743000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	29674000	USD
CY2021	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	2714000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	1311000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	0	USD
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-210099000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-163049000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-135063000	USD
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	7772000	USD
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	207000	USD
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-1727000	USD
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	9053000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	36614000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-27983000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	157515000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	120901000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	148884000	USD
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	166568000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	157515000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	120901000	USD
CY2021	us-gaap	Interest Paid Net InterestPaidNet	10330000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	13256000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	12310000	USD
CY2021	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	2100000	USD
CY2020	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	1400000	USD
CY2019	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	5200000	USD
CY2021	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	59111000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	55039000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	66038000	USD
CY2018Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	967100000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	158761000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-20866000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	-12125000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	125770000	USD
CY2019	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	287000	USD
CY2019	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.54
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	10334000	USD
CY2020	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	8715000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	29674000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	17618000	USD
CY2019	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-6893000	USD
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	11751000	USD
CY2019	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	6846000	USD
CY2019	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	100000000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	989464000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	173890000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	3435000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-4638000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	172687000	USD
CY2020	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	154000	USD
CY2020	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.64
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	34743000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	19424000	USD
CY2020	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-11166000	USD
CY2020	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	117188000	USD
CY2020Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1037373000	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
CY2021	us-gaap	Nature Of Operations NatureOfOperations	Description of Business<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 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 consulting and engineering projects and include applied science, data analysis, research, engineering, design, project management, and operations and maintenance.</span>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. We continue to report the historical results of the wind-down of our non-core construction activities in the Remediation and Construction Management (“RCM”) reportable segment.
CY2021	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2021	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 52/53-week periods ending on the Sunday nearest September 30. Fiscal 2021 contained 53 weeks, and fiscal 2020 and 2019 each contained 52 weeks.</span>
CY2021	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>
CY2021	ttek	Maximum Term Of Original Maturity To Classify An Instrument As Cash Equivalent MaximumTermOfOriginalMaturityToClassifyAnInstrumentAsCashEquivalent	P90D
CY2021	ttek	Unbilled Contracts Receivable Period For Billing And Collection UnbilledContractsReceivablePeriodForBillingAndCollection	P12M
CY2021	ttek	Number Of Levels Below Segments For Goodwill Impairment Testing NumberOfLevelsBelowSegmentsForGoodwillImpairmentTesting	1	level
CY2021	ttek	Number Of Levels Below Segments For Goodwill Impairment Testing NumberOfLevelsBelowSegmentsForGoodwillImpairmentTesting	1	level
CY2021	ttek	Concentration Of Credit Risk Number Of Financial Institutions For Investment Exposure ConcentrationOfCreditRiskNumberOfFinancialInstitutionsForInvestmentExposure	1	Institution
CY2021Q4	ttek	Percentage Of Account Receivables Due From Agencies PercentageOfAccountReceivablesDueFromAgencies	0.24
CY2020Q3	us-gaap	Contract With Customer Asset Net Current ContractWithCustomerAssetNetCurrent	92632000	USD
CY2021Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	190403000	USD
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	USD
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2994891000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3107348000	USD
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	USD
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2994891000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3107348000	USD
CY2021Q4	us-gaap	Contract With Customer Asset Net Current ContractWithCustomerAssetNetCurrent	103784000	USD
CY2020Q3	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	171905000	USD
CY2021Q4	ttek	Contract With Customer Asset Liability Net Current ContractWithCustomerAssetLiabilityNetCurrent	-86619000	USD
CY2020Q3	ttek	Contract With Customer Asset Liability Net Current ContractWithCustomerAssetLiabilityNetCurrent	-79273000	USD
CY2021	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	119000000	USD
CY2020	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	118000000	USD
CY2021	us-gaap	Contract With Customer Liability Cumulative Catch Up Adjustment To Revenue Change In Measure Of Progress ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress	700000	USD
CY2020	us-gaap	Contract With Customer Liability Cumulative Catch Up Adjustment To Revenue Change In Measure Of Progress ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress	800000	USD
CY2021Q4	us-gaap	Provision For Loss On Contracts ProvisionForLossOnContracts	12700000	USD
CY2020Q3	us-gaap	Provision For Loss On Contracts ProvisionForLossOnContracts	13200000	USD
CY2021Q4	ttek	Revenue Recognition Estimated Cost To Complete Related Contracts RevenueRecognitionEstimatedCostToCompleteRelatedContracts	104000000	USD
CY2020Q3	ttek	Revenue Recognition Estimated Cost To Complete Related Contracts RevenueRecognitionEstimatedCostToCompleteRelatedContracts	118000000	USD
CY2021Q4	us-gaap	Billed Contract Receivables BilledContractReceivables	432814000	USD
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	1436456000	USD
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	3467833000	USD
CY2021	ttek	Revenue Remaining Performance Obligation Termination Notice Period One RevenueRemainingPerformanceObligationTerminationNoticePeriodOne	P30D
CY2020Q3	us-gaap	Billed Contract Receivables BilledContractReceivables	402818000	USD
CY2021Q4	us-gaap	Unbilled Contracts Receivable UnbilledContractsReceivable	240536000	USD
CY2020Q3	us-gaap	Unbilled Contracts Receivable UnbilledContractsReceivable	253364000	USD
CY2021Q4	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	673350000	USD
CY2020Q3	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	656182000	USD
CY2021Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	4352000	USD
CY2020Q3	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	7147000	USD
CY2021Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	668998000	USD
CY2020Q3	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	649035000	USD
CY2021	ttek	Unbilled Contracts Receivable Period For Billing And Collection UnbilledContractsReceivablePeriodForBillingAndCollection	P12M
CY2021Q4	ttek	Government Contract Receivable Unbilled Amounts Related To Claims And Requests For Equitable Adjustment On Contract GovernmentContractReceivableUnbilledAmountsRelatedToClaimsAndRequestsForEquitableAdjustmentOnContract	11000000	USD
CY2020Q3	ttek	Government Contract Receivable Unbilled Amounts Related To Claims And Requests For Equitable Adjustment On Contract GovernmentContractReceivableUnbilledAmountsRelatedToClaimsAndRequestsForEquitableAdjustmentOnContract	14000000	USD
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	3500000000	USD
CY2021Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	2031377000	USD
CY2021	ttek	Revenue Remaining Performance Obligation Termination Notice Period Two RevenueRemainingPerformanceObligationTerminationNoticePeriodTwo	P60Y
CY2021	ttek	Revenue Remaining Performance Obligation Termination Notice Period Three RevenueRemainingPerformanceObligationTerminationNoticePeriodThree	P90D
CY2020Q3	us-gaap	Stock Repurchase Program Remaining Authorized Repurchase Amount1 StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1	207800000	USD
CY2021	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	479369	shares
CY2021	ttek	Stock Repurchased During Period Average Price Per Share StockRepurchasedDuringPeriodAveragePricePerShare	125.16
CY2021	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	60000000	USD
CY2021Q4	us-gaap	Stock Repurchase Program Remaining Authorized Repurchase Amount1 StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1	147800000	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
CY2021Q2	us-gaap	Dividends Dividends	10831000	USD
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
CY2019Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.15
CY2019Q4	us-gaap	Dividends Dividends	8190000	USD
CY2020Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.15
CY2020Q1	us-gaap	Dividends Dividends	8225000	USD
CY2020Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.17
CY2020Q2	us-gaap	Dividends Dividends	9175000	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.17
CY2020Q3	us-gaap	Dividends Dividends	9153000	USD
CY2020	us-gaap	Dividends Dividends	34743000	USD
CY2021Q4	us-gaap	Stock Repurchase Program Remaining Authorized Repurchase Amount1 StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1	147800000	USD
CY2019	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	10400000	USD
CY2021	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	3300000	USD
CY2020	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	15000000	USD
CY2019	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	-1100000	USD
CY2021Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	59300000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	924820000	USD
CY2020	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	80176000	USD
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	15800000	USD
CY2020	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	4302000	USD
CY2020Q3	us-gaap	Goodwill Goodwill	993498000	USD
CY2021	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	90591000	USD
CY2021	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	24489000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	175136000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	1108578000	USD
CY2021Q2	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2021Q4	us-gaap	Reporting Unit Percentage Of Fair Value In Excess Of Carrying Amount ReportingUnitPercentageOfFairValueInExcessOfCarryingAmount	1.50
CY2021Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	118971000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	80981000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	37990000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	106421000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	92478000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	13943000	USD
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11500000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11600000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11600000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	9664000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	7591000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	4983000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	4348000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	3967000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	7437000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	37990000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	131242000	USD
CY2020Q3	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	125511000	USD
CY2021Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	93509000	USD
CY2020Q3	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	90004000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	37733000	USD
CY2020Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	35507000	USD
CY2021	us-gaap	Depreciation Depreciation	12300000	USD
CY2020	us-gaap	Depreciation Depreciation	13000000	USD
CY2019	us-gaap	Depreciation Depreciation	17300000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	211222000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	209443000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	185535000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	55648000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	18548000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-10399000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	266870000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	227991000	USD
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	41056000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	24102000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	30051000	USD
CY2021	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	9893000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	6872000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	8923000	USD
CY2021	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	18887000	USD
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	20398000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	15016000	USD
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	69836000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	51372000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	53990000	USD
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-6034000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	2187000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-9108000	USD
CY2021	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-2060000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	870000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-1195000	USD
CY2021	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-27703000	USD
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-328000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-27312000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-35797000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	2729000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-37615000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	34039000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	54101000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	16375000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2021	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.023
CY2020	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.027
CY2019	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.033
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.026
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.022
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.047
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.009
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.007
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.010
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.010
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.011
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.017
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Impairment Losses EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses	0
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Impairment Losses EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses	0.015
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Impairment Losses EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses	0.009
CY2021	ttek	Effective Income Tax Rate Reconciliation Sharebased Payment Arrangement Percent EffectiveIncomeTaxRateReconciliationSharebasedPaymentArrangementPercent	-0.033
CY2020	ttek	Effective Income Tax Rate Reconciliation Sharebased Payment Arrangement Percent EffectiveIncomeTaxRateReconciliationSharebasedPaymentArrangementPercent	-0.022
CY2019	ttek	Effective Income Tax Rate Reconciliation Sharebased Payment Arrangement Percent EffectiveIncomeTaxRateReconciliationSharebasedPaymentArrangementPercent	-0.024
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.093
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.016
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.135
CY2021	ttek	Effective Income Tax Rate Reconciliation Change In Uncertain Tax Positions Percent EffectiveIncomeTaxRateReconciliationChangeInUncertainTaxPositionsPercent	0.017
CY2020	ttek	Effective Income Tax Rate Reconciliation Change In Uncertain Tax Positions Percent EffectiveIncomeTaxRateReconciliationChangeInUncertainTaxPositionsPercent	0.004
CY2019	ttek	Effective Income Tax Rate Reconciliation Change In Uncertain Tax Positions Percent EffectiveIncomeTaxRateReconciliationChangeInUncertainTaxPositionsPercent	0.024
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	-0.037
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	0.008
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Prior Year Income Taxes EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes	-0.002
CY2021	ttek	Effective Income Tax Rate Reconciliation Nondeductible Expense Employee Compensation Percent EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEmployeeCompensationPercent	0.020
CY2020	ttek	Effective Income Tax Rate Reconciliation Nondeductible Expense Employee Compensation Percent EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEmployeeCompensationPercent	0.002
CY2019	ttek	Effective Income Tax Rate Reconciliation Nondeductible Expense Employee Compensation Percent EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEmployeeCompensationPercent	0.002
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Repatriation Of Foreign Earnings EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings	0.021
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Repatriation Of Foreign Earnings EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings	0
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Repatriation Of Foreign Earnings EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings	0
CY2021	ttek	Effective Income Tax Rate Reconciliation Unremitted Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationUnremittedForeignEarningsPercent	0.010
CY2020	ttek	Effective Income Tax Rate Reconciliation Unremitted Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationUnremittedForeignEarningsPercent	0
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent	0
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent	0
CY2019	ttek	Effective Income Tax Rate Reconciliation Unremitted Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationUnremittedForeignEarningsPercent	0
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent	-0.014
CY2021	ttek	Effective Income Tax Rate Reconciliation Other Non Recurring Adjustments To Deferred Taxes Percent EffectiveIncomeTaxRateReconciliationOtherNonRecurringAdjustmentsToDeferredTaxesPercent	0.008
CY2020	ttek	Effective Income Tax Rate Reconciliation Other Non Recurring Adjustments To Deferred Taxes Percent EffectiveIncomeTaxRateReconciliationOtherNonRecurringAdjustmentsToDeferredTaxesPercent	-0.013
CY2019	ttek	Effective Income Tax Rate Reconciliation Other Non Recurring Adjustments To Deferred Taxes Percent EffectiveIncomeTaxRateReconciliationOtherNonRecurringAdjustmentsToDeferredTaxesPercent	-0.004
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Transition Tax On Accumulated Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017TransitionTaxOnAccumulatedForeignEarningsPercent	0
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Transition Tax On Accumulated Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017TransitionTaxOnAccumulatedForeignEarningsPercent	0
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Transition Tax On Accumulated Foreign Earnings Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017TransitionTaxOnAccumulatedForeignEarningsPercent	0.014
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.009
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.016
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.034
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.128
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.237
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.093
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.128
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.237
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.093
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-12900000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-8300000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Amount EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount	-6400000	USD
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
CY2020	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	0.256
CY2019	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	0.246
CY2021Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	1342000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	1146000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	6662000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	6262000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	5917000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	6283000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	41657000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	28223000	USD
CY2021Q4	ttek	Deferred Tax Assets Leasing Arrangements DeferredTaxAssetsLeasingArrangements	60181000	USD
CY2020Q3	ttek	Deferred Tax Assets Leasing Arrangements DeferredTaxAssetsLeasingArrangements	66941000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	3560000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	5905000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	54825000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	43475000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	13040000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	24395000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	161104000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	133840000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	5595000	USD
CY2020Q3	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	14451000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	8136000	USD
CY2020Q3	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	5967000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	60181000	USD
CY2020Q3	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	66941000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	40121000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	800000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	800000	USD
CY2020Q3	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	29130000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	3136000	USD
CY2020Q3	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	0	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	85000	USD
CY2020Q3	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	1615000	USD
CY2021Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	117254000	USD
CY2020Q3	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	118104000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	43850000	USD
CY2020Q3	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	15736000	USD
CY2021Q4	us-gaap	Undistributed Earnings Of Foreign Subsidiaries UndistributedEarningsOfForeignSubsidiaries	50900000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	13000000	USD
CY2021Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	12900000	USD
CY2020Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	9228000	USD
CY2019Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	9169000	USD
CY2018Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	8328000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	2171000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	700000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1342000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	1500000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	356000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	641000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	100000	USD
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	757000	USD
CY2021Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	12899000	USD
CY2020Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	9228000	USD
CY2019Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	9169000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	2600000	USD
CY2021	us-gaap	Tax Adjustments Settlements And Unusual Provisions TaxAdjustmentsSettlementsAndUnusualProvisions	0	USD
CY2020	us-gaap	Tax Adjustments Settlements And Unusual Provisions TaxAdjustmentsSettlementsAndUnusualProvisions	0	USD
CY2019	us-gaap	Tax Adjustments Settlements And Unusual Provisions TaxAdjustmentsSettlementsAndUnusualProvisions	-200000	USD
CY2021Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	5200000	USD
CY2020Q3	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	4400000	USD
CY2019Q3	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	3600000	USD
CY2021Q4	us-gaap	Long Term Debt LongTermDebt	212500000	USD
CY2020Q3	us-gaap	Long Term Debt LongTermDebt	291659000	USD
CY2021Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	12500000	USD
CY2020Q3	us-gaap	Long Term Debt Current LongTermDebtCurrent	49264000	USD
CY2021Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	200000000	USD
CY2020Q3	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	242395000	USD
CY2021Q4	us-gaap	Bank Overdrafts BankOverdrafts	0	USD
CY2021	ttek	Lease Cost Other LeaseCostOther	0	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	12500000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	200000000	USD
CY2021Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	212500000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Renewal Term LesseeOperatingLeaseRenewalTerm	P5Y
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	91076000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	87348000	USD
CY2021	us-gaap	Sublease Income SubleaseIncome	106000	USD
CY2020	us-gaap	Sublease Income SubleaseIncome	2216000	USD
CY2020Q3	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	191955000	USD
CY2020	ttek	Lease Cost Other LeaseCostOther	72000	USD
CY2021	us-gaap	Lease Cost LeaseCost	90970000	USD
CY2020	us-gaap	Lease Cost LeaseCost	85204000	USD
CY2021	us-gaap	Operating Lease Payments OperatingLeasePayments	81943000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	80289000	USD
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	72076000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	317587000	USD
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	215422000	USD
CY2020Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	239396000	USD
CY2021Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	67452000	USD
CY2020Q3	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	69650000	USD
CY2021Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	174285000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	241737000	USD
CY2020Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	261605000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	15499000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	241737000	USD
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y
CY2020Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.022
CY2020Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.025
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	71913000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	55528000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	40512000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	29521000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	19643000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	40119000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	257236000	USD
CY2019	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	79300000	USD
CY2021	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	23067000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	19424000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	17618000	USD
CY2021	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4910000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4318000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4016000	USD
CY2021	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	18157000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	15106000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	13602000	USD
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue	24149000	USD
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	179000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	37.05
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P4Y8M19D
CY2020Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	539000	shares
CY2020Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	36.34
CY2021	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	324000	shares
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	34.70
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	1000	shares
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	40.80
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	214000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	38.80
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y11M12D
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	24149000	USD
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber	214000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice	38.80
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P4Y11M12D
CY2021Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	20600000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2021	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	26900000	USD
CY2020	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	25000000	USD
CY2019	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	23300000	USD
CY2021Q4	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	41400000	USD
CY2020Q3	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	35100000	USD
CY2021Q4	us-gaap	Deferred Compensation Liability Classified Noncurrent DeferredCompensationLiabilityClassifiedNoncurrent	41100000	USD
CY2020Q3	us-gaap	Deferred Compensation Liability Classified Noncurrent DeferredCompensationLiabilityClassifiedNoncurrent	35000000	USD
CY2021Q4	ttek	Defined Benefit Plan Pension Plan Open For New Entrants Maximum Age DefinedBenefitPlanPensionPlanOpenForNewEntrantsMaximumAge	P24Y
CY2021Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	65836000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	64830000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	1006000	USD
CY2021Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	65836000	USD
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54675000	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	55022000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	55936000	shares
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.31
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.21
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	232810000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	173859000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	158668000	USD
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54078000	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54235000	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54986000	shares
CY2021	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	597000	shares
CY2020	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	787000	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	950000	shares
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.89
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.26
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.16
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.84
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2020	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
CY2019Q3	ttek	Loss Contingency Number Of Actions LossContingencyNumberOfActions	3	action
CY2021	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	USD
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2994891000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3107348000	USD
CY2021	us-gaap	Operating Income Loss OperatingIncomeLoss	278701000	USD
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	241091000	USD
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	188762000	USD
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11500000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11600000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	11600000	USD
CY2021	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	3300000	USD
CY2020	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	15000000	USD
CY2019	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	-1100000	USD
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	15800000	USD
CY2019	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	7800000	USD
CY2021Q4	us-gaap	Assets Assets	2576562000	USD
CY2020Q3	us-gaap	Assets Assets	2378558000	USD
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3213513000	USD
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2994891000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3107348000	USD
CY2021Q4	us-gaap	Noncurrent Assets NoncurrentAssets	303460000	USD
CY2020Q3	us-gaap	Noncurrent Assets NoncurrentAssets	339281000	USD
CY2020Q3	us-gaap	Due To Related Parties Current And Noncurrent DueToRelatedPartiesCurrentAndNoncurrent	478000	USD
CY2020Q1	ttek	Covid19 Incremental Costs COVID19IncrementalCosts	8200000	USD
CY2021	us-gaap	Related Party Transaction Other Revenues From Transactions With Related Party RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty	95500000	USD
CY2020	us-gaap	Related Party Transaction Other Revenues From Transactions With Related Party RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty	88200000	USD
CY2019	us-gaap	Related Party Transaction Other Revenues From Transactions With Related Party RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty	99100000	USD
CY2021	us-gaap	Related Party Transaction Expenses From Transactions With Related Party RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty	92400000	USD
CY2020	us-gaap	Related Party Transaction Expenses From Transactions With Related Party RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty	86400000	USD
CY2019	us-gaap	Related Party Transaction Expenses From Transactions With Related Party RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty	98500000	USD
CY2021Q4	us-gaap	Accounts Receivable Related Parties AccountsReceivableRelatedParties	19082000	USD
CY2020Q3	us-gaap	Accounts Receivable Related Parties AccountsReceivableRelatedParties	20884000	USD
CY2021Q4	ttek	Contract With Customer Asset Related Party ContractWithCustomerAssetRelatedParty	5092000	USD
CY2020Q3	ttek	Contract With Customer Asset Related Party ContractWithCustomerAssetRelatedParty	3261000	USD
CY2021Q4	us-gaap	Due To Related Parties Current And Noncurrent DueToRelatedPartiesCurrentAndNoncurrent	3026000	USD
CY2020Q3	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	15800000	USD
CY2019Q4	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	800000	USD
CY2020Q1	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	2200000	USD
CY2020Q2	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	4500000	USD
CY2020Q3	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	1000000	USD
CY2020Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	765104000	USD
CY2021Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	754764000	USD
CY2021Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	801633000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	892012000	USD
CY2020Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	66252000	USD
CY2021Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	60807000	USD
CY2021Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	69807000	USD
	us-gaap	Operating Income Loss OperatingIncomeLoss	81836000	USD
CY2020Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	52436000	USD
CY2021Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	45517000	USD
CY2021Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	51903000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	82954000	USD
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.97
CY2021Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.84
CY2021Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.96
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.54
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.96
CY2021Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.83
CY2021Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.95
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.52
CY2020Q4	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53927000	shares
CY2021Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54187000	shares
CY2021Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54117000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54019000	shares
CY2020Q4	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54637000	shares
CY2021Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54736000	shares
CY2021Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54666000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54597000	shares
CY2019Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	797623000	USD
CY2020Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	734133000	USD
CY2020Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	709771000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	753364000	USD
CY2019Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	63302000	USD
CY2020Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	47530000	USD
CY2020Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	63525000	USD
CY2020Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	66735000	USD
CY2019Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	47310000	USD
CY2020Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	36397000	USD
CY2020Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	45497000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	44654000	USD
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.87
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.67
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.84
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.83
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.85
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.66
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.83
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.82
CY2019Q4	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54560000	shares
CY2020Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	54699000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53985000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	53841000	shares
CY2019Q4	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	55438000	shares
CY2020Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	55463000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54692000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	54603000	shares

Files In Submission

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ttek-ex95q410x3x2021.htm	Edgar Link	pending

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$TTEK
TETRA TECH INC Stock $ttek

2021 Q4 Form 10-K Financial Statement

#000083164121000110 Filed on November 24, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$TTEK TETRA TECH INC Stock $ttek

2021 Q4 Form 10-K Financial Statement

#000083164121000110 Filed on November 24, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$TTEK
TETRA TECH INC Stock $ttek