$TTEK
TETRA TECH INC Stock $ttek

$ttek Overview Financials Valuation SEC Filings Company Website

2011 Q4 Form 10-K Financial Statement

#000104746912010616 Filed on November 15, 2012

Income Statement

Concept	2011 Q4	2011 Q3	2011 Q2
Revenue	$675.7M	$673.8M	$612.6M
YoY Change	60.6%		65.51%
Cost Of Revenue	$377.6M	$395.6M	$351.2M
YoY Change	11.49%		17.97%
Gross Profit	$98.40M	$84.90M	$79.10M
YoY Change	20.0%		9.25%
Gross Profit Margin	14.56%	12.6%	12.91%
Selling, General & Admin	$54.90M	$45.50M	$49.80M
YoY Change	22.27%		25.44%
% of Gross Profit	55.79%	53.59%	62.96%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$14.10M	$14.20M	$13.80M
YoY Change	50.0%		70.37%
% of Gross Profit	14.33%	16.73%	17.45%
Operating Expenses	$54.90M	$45.50M	$49.80M
YoY Change	22.27%		25.44%
Operating Profit	$43.43M	$39.41M	$29.26M
YoY Change	17.07%		-10.53%
Interest Expense	-$1.500M	-$1.700M	-$1.500M
YoY Change	275.0%		400.0%
% of Operating Profit	-3.45%	-4.31%	-5.13%
Other Income/Expense, Net
YoY Change
Pretax Income	$42.00M	$37.70M	$27.80M
YoY Change	14.44%		-14.2%
Income Tax	$14.60M	$13.00M	$9.700M
% Of Pretax Income	34.76%	34.48%	34.89%
Net Earnings	$26.40M	$23.80M	$17.50M
YoY Change	14.29%		-15.05%
Net Earnings / Revenue	3.91%	3.53%	2.86%
Basic Earnings Per Share	$0.42	$0.38	$0.28
Diluted Earnings Per Share	$0.42	$0.38	$0.28
COMMON SHARES
Basic Shares Outstanding	62.31M shares	62.20M shares	62.12M shares
Diluted Shares Outstanding	62.86M shares	62.93M shares	62.95M shares

Balance Sheet

Concept	2011 Q4	2011 Q3	2011 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$90.50M	$98.40M	$90.90M
YoY Change	-59.03%		-24.44%
Cash & Equivalents	$90.49M	$98.40M	$90.90M
Short-Term Investments
Other Short-Term Assets	$84.60M	$53.00M	$53.40M
YoY Change	69.54%		4.5%
Inventory
Prepaid Expenses
Receivables	$657.2M	$655.2M	$585.2M
Other Receivables	$22.40M	$23.30M	$21.70M
Total Short-Term Assets	$839.1M	$829.9M	$751.3M
YoY Change	-0.66%		7.91%
LONG-TERM ASSETS
Property, Plant & Equipment	$77.54M	$80.60M	$83.90M
YoY Change	-2.35%		18.67%
Goodwill	$569.4M
YoY Change	44.37%
Intangibles	$81.05M
YoY Change
Long-Term Investments	$3.454M	$3.400M	$3.300M
YoY Change	3354.0%
Other Assets	$23.43M	$22.10M	$22.00M
YoY Change	37.82%		33.33%
Total Long-Term Assets	$754.9M	$741.9M	$748.9M
YoY Change	40.57%		62.98%
TOTAL ASSETS
Total Short-Term Assets	$839.1M	$829.9M	$751.3M
Total Long-Term Assets	$754.9M	$741.9M	$748.9M
Total Assets	$1.594B	$1.572B	$1.500B
YoY Change	15.36%		29.81%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$164.8M	$184.4M	$136.3M
YoY Change	-1.01%		-10.86%
Accrued Expenses	$110.9M	$120.5M	$94.90M
YoY Change	18.99%		30.72%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$2.600M	$2.800M	$4.400M
YoY Change	-48.0%		-15.38%
Total Short-Term Liabilities	$531.7M	$511.4M	$436.6M
YoY Change	13.81%		6.7%
LONG-TERM LIABILITIES
Long-Term Debt	$144.9M	$112.7M	$141.7M
YoY Change	18.29%		3195.35%
Other Long-Term Liabilities	$36.77M	$52.00M	$50.50M
YoY Change	17.47%		294.53%
Total Long-Term Liabilities	$36.77M	$164.7M	$192.2M
YoY Change	-76.09%		1023.98%
TOTAL LIABILITIES
Total Short-Term Liabilities	$531.7M	$511.4M	$436.6M
Total Long-Term Liabilities	$36.77M	$164.7M	$192.2M
Total Liabilities	$568.5M	$717.9M	$676.9M
YoY Change	-10.28%		55.57%
SHAREHOLDERS EQUITY
Retained Earnings	$449.9M
YoY Change
Common Stock	$400.0M
YoY Change
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$854.7M	$853.9M	$823.2M
YoY Change
Total Liabilities & Shareholders Equity	$1.594B	$1.572B	$1.500B
YoY Change	15.36%		29.81%

Cashflow Statement

Concept	2011 Q4	2011 Q3	2011 Q2
OPERATING ACTIVITIES
Net Income	$26.40M	$23.80M	$17.50M
YoY Change	14.29%		-15.05%
Depreciation, Depletion And Amortization	$14.10M	$14.20M	$13.80M
YoY Change	50.0%		70.37%
Cash From Operating Activities	$33.20M	$55.80M	$33.70M
YoY Change	-21.33%		37.55%
INVESTING ACTIVITIES
Capital Expenditures	-$5.300M	-$4.100M	-$5.300M
YoY Change	-7.02%		-17.19%
Acquisitions
YoY Change
Other Investing Activities	-$68.70M	-$18.20M	-$21.30M
YoY Change	26.06%		99.07%
Cash From Investing Activities	-$74.00M	-$22.30M	-$26.50M
YoY Change	22.72%		55.88%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	33.40M	-26.40M	1.800M
YoY Change	-71.77%		350.0%
NET CHANGE
Cash From Operating Activities	33.20M	55.80M	33.70M
Cash From Investing Activities	-74.00M	-22.30M	-26.50M
Cash From Financing Activities	33.40M	-26.40M	1.800M
Net Change In Cash	-7.400M	7.100M	9.000M
YoY Change	-107.39%		13.92%
FREE CASH FLOW
Cash From Operating Activities	$33.20M	$55.80M	$33.70M
Capital Expenditures	-$5.300M	-$4.100M	-$5.300M
Free Cash Flow	$38.50M	$59.90M	$39.00M
YoY Change	-19.62%		26.21%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2011Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	90494000	USD
CY2011Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	657179000	USD
CY2011Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	84612000	USD
CY2011Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	6817000	USD
CY2011Q4	us-gaap	Assets Current AssetsCurrent	839102000	USD
CY2011Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	77536000	USD
CY2011Q4	us-gaap	Equity Method Investments EquityMethodInvestments	3454000	USD
CY2011Q4	us-gaap	Goodwill Goodwill	569414000	USD
CY2011Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	81053000	USD
CY2011Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	23429000	USD
CY2011Q4	us-gaap	Assets Assets	1593988000	USD
CY2011Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	164819000	USD
CY2011Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	110937000	USD
CY2011Q4	us-gaap	Billings In Excess Of Cost Current BillingsInExcessOfCostCurrent	84754000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Current DeferredTaxLiabilitiesCurrent	22870000	USD
CY2011Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	2556000	USD
CY2011Q4	us-gaap	Business Acquisition Contingent Consideration Potential Cash Payment BusinessAcquisitionContingentConsiderationPotentialCashPayment	64119000	USD
CY2011Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	81654000	USD
CY2011Q4	us-gaap	Liabilities Current LiabilitiesCurrent	531709000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	25394000	USD
CY2011Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	144868000	USD
CY2011Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	36767000	USD
CY2011Q4	us-gaap	Preferred Stock Value PreferredStockValue		USD
CY2011Q4	us-gaap	Common Stock Value CommonStockValue	625000	USD
CY2011Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	399420000	USD
CY2011Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	4754000	USD
CY2011Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	449926000	USD
CY2011Q4	us-gaap	Stockholders Equity StockholdersEquity	854725000	USD
CY2011Q4	us-gaap	Minority Interest MinorityInterest	525000	USD
CY2011Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	855250000	USD
CY2011Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	1593988000	USD
CY2012Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	104848000	USD
CY2012Q3	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	700480000	USD
CY2012Q3	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	48168000	USD
CY2012Q3	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	5817000	USD
CY2012Q3	us-gaap	Assets Current AssetsCurrent	859313000	USD
CY2012Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	74309000	USD
CY2012Q3	us-gaap	Equity Method Investments EquityMethodInvestments	3279000	USD
CY2012Q3	us-gaap	Goodwill Goodwill	635958000	USD
CY2012Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	74231000	USD
CY2012Q3	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	23940000	USD
CY2012Q3	us-gaap	Assets Assets	1671030000	USD
CY2012Q3	us-gaap	Accounts Payable Current AccountsPayableCurrent	154003000	USD
CY2012Q3	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	128086000	USD
CY2012Q3	us-gaap	Billings In Excess Of Cost Current BillingsInExcessOfCostCurrent	90909000	USD
CY2012Q3	us-gaap	Deferred Tax Liabilities Current DeferredTaxLiabilitiesCurrent	20809000	USD
CY2012Q3	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	2031000	USD
CY2012Q3	us-gaap	Business Acquisition Contingent Consideration Potential Cash Payment BusinessAcquisitionContingentConsiderationPotentialCashPayment	35407000	USD
CY2012Q3	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	72549000	USD
CY2012Q3	us-gaap	Liabilities Current LiabilitiesCurrent	503794000	USD
CY2012Q3	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	24268000	USD
CY2012Q3	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	81047000	USD
CY2012Q3	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	42054000	USD
CY2012Q3	us-gaap	Common Stock Value CommonStockValue	638000	USD
CY2012Q3	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	433009000	USD
CY2012Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	31017000	USD
CY2012Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	554306000	USD
CY2012Q3	us-gaap	Stockholders Equity StockholdersEquity	1018970000	USD
CY2012Q3	us-gaap	Minority Interest MinorityInterest	897000	USD
CY2012Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1019867000	USD
CY2012Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	1671030000	USD
CY2012Q3	us-gaap	Preferred Stock Value PreferredStockValue		USD
CY2011Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	2000000	shares
CY2011Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2011Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2011Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	150000000	shares
CY2011Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2011Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	62495000	shares
CY2012Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	2000000	shares
CY2012Q3	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2012Q3	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2012Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	150000000	shares
CY2012Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2012Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	63837000	shares
CY2012	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	2711075000	USD
CY2012	ttek	Subcontractor Costs SubcontractorCosts	689005000	USD
CY2012	us-gaap	Other Cost Of Operating Revenue OtherCostOfOperatingRevenue	1663065000	USD
CY2012	ttek	Selling General And Administrative Expenses Including Depreciation And Amortization Of Intangible Assets SellingGeneralAndAdministrativeExpensesIncludingDepreciationAndAmortizationOfIntangibleAssets	211884000	USD
CY2012	us-gaap	Operating Income Loss OperatingIncomeLoss	166367000	USD
CY2012	us-gaap	Interest Expense InterestExpense	6444000	USD
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	160796000	USD
CY2012	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	56064000	USD
CY2012	us-gaap	Profit Loss ProfitLoss	104732000	USD
CY2012	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	352000	USD
CY2012	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	104380000	USD
CY2012	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.65
CY2012	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.63
CY2012	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	63217000	shares
CY2012	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	63934000	shares
CY2011	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	2573144000	USD
CY2011	ttek	Subcontractor Costs SubcontractorCosts	780817000	USD
CY2011	us-gaap	Other Cost Of Operating Revenue OtherCostOfOperatingRevenue	1454374000	USD
CY2011	ttek	Selling General And Administrative Expenses Including Depreciation And Amortization Of Intangible Assets SellingGeneralAndAdministrativeExpensesIncludingDepreciationAndAmortizationOfIntangibleAssets	193286000	USD
CY2011	us-gaap	Operating Income Loss OperatingIncomeLoss	146422000	USD
CY2010	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	2201232000	USD
CY2010	ttek	Subcontractor Costs SubcontractorCosts	741002000	USD
CY2010	us-gaap	Other Cost Of Operating Revenue OtherCostOfOperatingRevenue	1172542000	USD
CY2010	ttek	Selling General And Administrative Expenses Including Depreciation And Amortization Of Intangible Assets SellingGeneralAndAdministrativeExpensesIncludingDepreciationAndAmortizationOfIntangibleAssets	163479000	USD
CY2010	us-gaap	Operating Income Loss OperatingIncomeLoss	124474000	USD
CY2012	us-gaap	Investment Income Interest InvestmentIncomeInterest	873000	USD
CY2011	us-gaap	Investment Income Interest InvestmentIncomeInterest	879000	USD
CY2011	us-gaap	Interest Expense InterestExpense	6809000	USD
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	140492000	USD
CY2010	us-gaap	Investment Income Interest InvestmentIncomeInterest	801000	USD
CY2010	us-gaap	Interest Expense InterestExpense	2188000	USD
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	123087000	USD
CY2011	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	47510000	USD
CY2011	us-gaap	Profit Loss ProfitLoss	92982000	USD
CY2011	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	2943000	USD
CY2010	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	46268000	USD
CY2010	us-gaap	Profit Loss ProfitLoss	76819000	USD
CY2011	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	90039000	USD
CY2010	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	76819000	USD
CY2011	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.45
CY2011	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.43
CY2010	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.25
CY2010	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.24
CY2012	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	139000	USD
CY2012	us-gaap	Impairment Of Leasehold ImpairmentOfLeasehold	1261000	USD
CY2011	us-gaap	Proceeds From Issuance Of Long Term Debt And Capital Securities Net ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet	67618000	USD
CY2012	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-191000	USD
CY2011	us-gaap	Payments Of Dividends Minority Interest PaymentsOfDividendsMinorityInterest	1702000	USD
CY2011	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	62053000	shares
CY2011	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	62775000	shares
CY2010	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	61430000	shares
CY2010	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	62087000	shares
CY2012	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	56902000	USD
CY2012	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	-286000	USD
CY2012	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	2916000	USD
CY2012	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	3194000	USD
CY2012	us-gaap	Share Based Compensation ShareBasedCompensation	10839000	USD
CY2012	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	624000	USD
CY2012	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-5512000	USD
CY2012	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	4768000	USD
CY2011	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	18901000	USD
CY2011	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	269996000	USD
CY2011	us-gaap	Payments For Hedge Investing Activities PaymentsForHedgeInvestingActivities	4216000	USD
CY2012	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	39960000	USD
CY2012	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-26284000	USD
CY2012	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-14529000	USD
CY2012	ttek	Increase Decrease In Accrued Compensation IncreaseDecreaseInAccruedCompensation	15678000	USD
CY2012	us-gaap	Increase Decrease In Billing In Excess Of Cost Of Earnings IncreaseDecreaseInBillingInExcessOfCostOfEarnings	2425000	USD
CY2012	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	7371000	USD
CY2012	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	2665000	USD
CY2011	us-gaap	Proceeds From Hedge Investing Activities ProceedsFromHedgeInvestingActivities	3923000	USD
CY2011	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	5000000	USD
CY2012	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	158021000	USD
CY2012	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	25106000	USD
CY2012	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	55014000	USD
CY2012	us-gaap	Payments For Hedge Investing Activities PaymentsForHedgeInvestingActivities	4192000	USD
CY2012	us-gaap	Proceeds From Hedge Investing Activities ProceedsFromHedgeInvestingActivities	3906000	USD
CY2012	us-gaap	Payments To Acquire Interest In Joint Venture PaymentsToAcquireInterestInJointVenture	430000	USD
CY2012	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	1037000	USD
CY2012	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-79799000	USD
CY2012	us-gaap	Repayments Of Long Term Debt And Capital Securities RepaymentsOfLongTermDebtAndCapitalSecurities	120792000	USD
CY2012	us-gaap	Proceeds From Issuance Of Long Term Debt And Capital Securities Net ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet	52672000	USD
CY2011	ttek	Estimated Earn Out Liabilities For Acquisitions During The Period EstimatedEarnOutLiabilitiesForAcquisitionsDuringThePeriod	55622000	USD
CY2012	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	624000	USD
CY2012	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	18166000	USD
CY2011	us-gaap	Repayments Of Long Term Debt And Capital Securities RepaymentsOfLongTermDebtAndCapitalSecurities	43047000	USD
CY2011	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	104000	USD
CY2011	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	55684000	USD
CY2011	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	-293000	USD
CY2011	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	4877000	USD
CY2011	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	4802000	USD
CY2011	us-gaap	Share Based Compensation ShareBasedCompensation	10582000	USD
CY2011	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	104000	USD
CY2011	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	1720000	USD
CY2011	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	3733000	USD
CY2011	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	-1288000	USD
CY2011	us-gaap	Impairment Of Leasehold ImpairmentOfLeasehold	1281000	USD
CY2011	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	231000	USD
CY2010	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	33491000	USD
CY2011	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-34013000	USD
CY2011	ttek	Increase Decrease In Accrued Compensation IncreaseDecreaseInAccruedCompensation	11157000	USD
CY2010	us-gaap	Repayments Of Long Term Debt And Capital Securities RepaymentsOfLongTermDebtAndCapitalSecurities	2673000	USD
CY2010	us-gaap	Proceeds From Issuance Of Long Term Debt And Capital Securities Net ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet	120000000	USD
CY2010	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	754000	USD
CY2010	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	3353000	USD
CY2010	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	121434000	USD
CY2011	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents Continuing Operations EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations	428000	USD
CY2010	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents Continuing Operations EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations	861000	USD
CY2011	us-gaap	Increase Decrease In Billing In Excess Of Cost Of Earnings IncreaseDecreaseInBillingInExcessOfCostOfEarnings	-1669000	USD
CY2011	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	6475000	USD
CY2011	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	10553000	USD
CY2010	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	-28000	USD
CY2010	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1184000	USD
CY2010	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	1689000	USD
CY2010	us-gaap	Share Based Compensation ShareBasedCompensation	10178000	USD
CY2010	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	754000	USD
CY2010	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	11641000	USD
CY2010	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	7179000	USD
CY2010	us-gaap	Foreign Currency Transaction Gain Loss Unrealized ForeignCurrencyTransactionGainLossUnrealized	205000	USD
CY2010	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	1480000	USD
CY2011	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-2046000	USD
CY2011	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	28324000	USD
CY2010	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	23161000	USD
CY2011	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	131623000	USD
CY2010	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-5770000	USD
CY2010	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-10002000	USD
CY2010	ttek	Increase Decrease In Accrued Compensation IncreaseDecreaseInAccruedCompensation	4582000	USD
CY2010	us-gaap	Increase Decrease In Billing In Excess Of Cost Of Earnings IncreaseDecreaseInBillingInExcessOfCostOfEarnings	-19957000	USD
CY2010	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	9855000	USD
CY2010	us-gaap	Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable IncreaseDecreaseInIncomeTaxesPayableNetOfIncomeTaxesReceivable	2618000	USD
CY2010	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	106842000	USD
CY2011	us-gaap	Payments To Acquire Interest In Joint Venture PaymentsToAcquireInterestInJointVenture	530000	USD
CY2011	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	879000	USD
CY2011	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-293841000	USD
CY2010	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	21584000	USD
CY2010	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	78905000	USD
CY2010	us-gaap	Payments For Hedge Investing Activities PaymentsForHedgeInvestingActivities	3960000	USD
CY2010	us-gaap	Proceeds From Hedge Investing Activities ProceedsFromHedgeInvestingActivities	3932000	USD
CY2010	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	3128000	USD
CY2010	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-97389000	USD
CY2011	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	8378000	USD
CY2011	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	31351000	USD
CY2012	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	-67394000	USD
CY2012	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents Continuing Operations EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations	3526000	USD
CY2012	us-gaap	Interest Paid Net InterestPaidNet	5279000	USD
CY2011	us-gaap	Net Cash Provided By Used In Continuing Operations NetCashProvidedByUsedInContinuingOperations	-130439000	USD
CY2010	us-gaap	Net Cash Provided By Used In Continuing Operations NetCashProvidedByUsedInContinuingOperations	131748000	USD
CY2012	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	58126000	USD
CY2011	us-gaap	Interest Paid Net InterestPaidNet	4226000	USD
CY2011	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	33715000	USD
CY2012	us-gaap	Net Cash Provided By Used In Continuing Operations NetCashProvidedByUsedInContinuingOperations	14354000	USD
CY2010	us-gaap	Interest Paid Net InterestPaidNet	1287000	USD
CY2010	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	32407000	USD
CY2010Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	220933000	USD
CY2009Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	89185000	USD
CY2011	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Period Increase Decrease OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease	-13955000	USD
CY2012	dei	Entity Registrant Name EntityRegistrantName	TETRA TECH INC
CY2012	dei	Entity Central Index Key EntityCentralIndexKey	0000831641
CY2012	dei	Document Type DocumentType	10-K
CY2012	dei	Document Period End Date DocumentPeriodEndDate	2012-09-30
CY2012	dei	Amendment Flag AmendmentFlag	false
CY2012	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--09-30
CY2012	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2012	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2012Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	63843736	shares
CY2012	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2012
CY2012	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2010Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	748133000	USD
CY2009Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	646478000	USD
CY2010	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Period Increase Decrease OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease	6874000	USD
CY2010	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-337000	USD
CY2011	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	438000	USD
CY2010	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	83356000	USD
CY2011	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	79465000	USD
CY2011	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	670000	USD
CY2011	us-gaap	Noncontrolling Interest Increase From Business Combination NoncontrollingInterestIncreaseFromBusinessCombination	438000	USD
CY2011	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	-4567000	USD
CY2011	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	1702000	USD
CY2010	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	10178000	USD
CY2011	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	10582000	USD
CY2010	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	2513000	USD
CY2011	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	8004000	USD
CY2010	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	4742000	USD
CY2011	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	5249000	USD
CY2010	us-gaap	Adjustments To Additional Paid In Capital Tax Effect From Share Based Compensation AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation	866000	USD
CY2011	us-gaap	Adjustments To Additional Paid In Capital Tax Effect From Share Based Compensation AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation	-156000	USD
CY2012	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Period Increase Decrease OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease	26486000	USD
CY2012	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-194000	USD
CY2012	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	131024000	USD
CY2012	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	9000	USD
CY2012	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	17535000	USD
CY2012	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	5300000	USD
CY2012	us-gaap	Adjustments To Additional Paid In Capital Tax Effect From Share Based Compensation AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation	-72000	USD
CY2012	us-gaap	Nature Of Operations NatureOfOperations	<table style="font-size:10pt; font-family:'Times New Roman',times,serif;"> <tr> <td> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2"><b>1.     Description of Business </b></font></p> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2">        We are a leading provider of consulting, engineering, program management, construction management, construction and technical services that focuses on addressing fundamental needs for water, the environment, energy, infrastructure and natural resources. We are a full-service company that leads with science. We typically begin at the earliest stage of a project by identifying technical solutions to problems and developing execution plans tailored to our clients' needs and resources. Our solutions may span the entire life cycle of consulting and engineering projects and include applied science, research and technology, engineering, design, construction management, construction, operations and maintenance, and information technology. </font></p></td></tr></table>
CY2012	ttek	Number Of Levels Below Reportable Segments For Goodwill Impairment Testing NumberOfLevelsBelowReportableSegmentsForGoodwillImpairmentTesting	1	level
CY2012	us-gaap	Fiscal Period FiscalPeriod	<table style="font-size:10pt; font-family:'Times New Roman',times,serif;"> <tr> <td><font size="2"><b><i>Fiscal Year.</i></b></font><font size="2">    We report results of operations based on 52 or 53-week periods ending near September 30 of each year. Fiscal years 2012, 2011 and 2010 contained 52, 52 and 53 weeks, respectively.</font></td></tr></table>
CY2012	us-gaap	Use Of Estimates UseOfEstimates	<table style="font-size:10pt; font-family:'Times New Roman',times,serif;"> <tr> <td><font size="2"><b><i>Use of Estimates.</i></b></font><font size="2">    The preparation of financial statements in conformity with 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.</font></td></tr></table>
CY2012	us-gaap	Revenue Recognition Long Term Contracts RevenueRecognitionLongTermContracts	<table style="font-size:10pt; font-family:'Times New Roman',times,serif;"> <tr> <td> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2"><b><i>Revenue Recognition and Contract Costs.</i></b></font><font size="2">    We recognize revenue for most of our contracts using the percentage-of-completion method, primarily based on contract costs incurred to date compared to total estimated contract costs. We generally utilize the cost-to-cost approach to estimate the progress towards completion in order to determine the amount of revenue and profit to recognize. Certain of our contracts are service-related contracts, such as providing operations and maintenance services or a variety of technical assistance services. Our service contracts are accounted for using the proportional performance method under which revenue is recognized in proportion to the number of service activities performed, in proportion to the direct costs of performing the service activities, or evenly across the period of performance depending upon the nature of the services provided. </font></p> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2">        We recognize revenue for work performed under three major types of contracts: fixed-price, time-and-materials and cost-plus. </font></p> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2"><i>        Fixed-Price.</i></font><font size="2">    We enter into two major types of fixed-price contracts: FFP and FPPU. Under FFP contracts, our clients pay us an agreed fixed-amount negotiated in advance for a specified scope of work. We generally recognize revenue on FFP contracts using the percentage-of-completion method. If the nature or circumstances of the contract prevent us from preparing a reliable estimate at completion, we will delay profit recognition until adequate information about the contract's progress becomes available. Under our FPPU contracts, clients pay us a set fee for each service or production transaction that we complete. Accordingly, we recognize revenue under FPPU contracts as we complete the related service or production transactions, generally using the proportional performance method. </font></p> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2"><i>        Time-and-Materials.</i></font><font size="2">    Under time-and-materials contracts, we negotiate hourly billing rates and charge our clients based on the actual time that we spend on a project. In addition, clients reimburse us for our actual out-of-pocket costs for materials and other direct incidental expenditures that we incur in connection with our performance under the contract. The majority of our time-and-material contracts are subject to maximum contract values and, accordingly, revenue under these contracts is generally recognized under the percentage-of-completion method. However, time and materials contracts that are service-related contracts are accounted for utilizing the proportional performance method. Revenue on contracts that are not subject to maximum contract values is recognized based on the actual number of hours we spend on the projects plus any actual out-of-pocket costs of materials and other direct incidental expenditures that we incur on the projects. Our time-and-materials contracts also generally include annual billing rate adjustment provisions. </font></p> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2"><i>        Cost-Plus.</i></font><font size="2">    Under cost-plus contracts, we are reimbursed for allowable or otherwise defined costs incurred plus a fee or mark-up. The contracts may also include incentives for various performance criteria, including quality, timeliness, ingenuity, safety and cost-effectiveness. In addition, our costs are generally subject to review by our clients and regulatory audit agencies, and such reviews could result in costs being disputed as non-reimbursable under the terms of the contract. Revenue for cost-plus contracts is recognized at the time services are performed based upon the amounts we expect to realize using the percentage-of-completion method. Revenue is not recognized for non-recoverable costs. Performance incentives are included in our estimates of revenue when their realization is reasonably assured. </font></p> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2">        If estimated total costs on any contract indicate a loss, we recognize the entire estimated loss in the period the loss becomes known. The cumulative effect of revisions to revenue; estimated costs to complete contracts, including penalties, incentive awards, change orders, claims, liquidated damages, anticipated losses, and other revisions are recorded in the period in which the revisions are identified and the loss can be reasonably estimated. Such revisions could occur in any reporting period and the effects may be material depending on the size of the project or the adjustment. </font></p> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2">        Once contract performance is underway, we may experience changes in conditions, client requirements, specifications, designs, materials and expectations regarding the period of performance. Such changes are "change orders" and may be initiated by us or by our clients. In many cases, agreement with the client as to the terms of change orders is reached prior to work commencing; however, sometimes circumstances require that work progress without obtaining client agreement. Revenue related to change orders is recognized as costs are incurred. Change orders that are unapproved as to both price and scope are evaluated as claims. </font></p> <p style="FONT-FAMILY: times; TEXT-ALIGN: justify"><font size="2">        Claims are amounts in excess of agreed contract prices that we seek to collect from our clients or other third parties for delays, errors in specifications and designs, contract terminations, change orders in dispute or unapproved as to both scope and price, or other causes of unanticipated additional costs. Revenue on claims is recognized only to the extent that contract costs related to the claims have been incurred and when it is probable that the claim will result in a bona fide addition to contract value that can be reliably estimated. No profit is recognized on a claim until final settlement occurs. This can lead to a situation in which costs are recognized in one period and revenue is recognized in a subsequent period when a client agreement is obtained or a claims resolution occurs.</font></p></td></tr></table>
CY2012	ttek	Number Of Weeks In Fiscal Year Low End Of Range NumberOfWeeksInFiscalYearLowEndOfRange	52
CY2012	ttek	Number Of Weeks In Fiscal Year High End Of Range NumberOfWeeksInFiscalYearHighEndOfRange	53
CY2012	ttek	Number Of Weeks In Fiscal Year NumberOfWeeksInFiscalYear	52
CY2011	ttek	Number Of Weeks In Fiscal Year NumberOfWeeksInFiscalYear	52
CY2010	ttek	Number Of Weeks In Fiscal Year NumberOfWeeksInFiscalYear	53
CY2012	ttek	Number Of Types Of Contracts For Revenue Recognition NumberOfTypesOfContractsForRevenueRecognition	3	contract
CY2012	ttek	Number Of Types Of Fixed Price Contracts NumberOfTypesOfFixedPriceContracts	2	contract
CY2012	ttek	Maximum Term Of Original Maturity To Classify An Instrument As Cash Equivalent MaximumTermOfOriginalMaturityToClassifyAnInstrumentAsCashEquivalent	90
CY2012Q3	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	5000000	USD
CY2012	ttek	Unbilled Contracts Receivable Period For Billing And Collection UnbilledContractsReceivablePeriodForBillingAndCollection	12
CY2012	ttek	Billings In Excess Of Cost Period For Revenue Recognition BillingsInExcessOfCostPeriodForRevenueRecognition	12
CY2012	us-gaap	Finite Lived Intangible Assets Useful Life Minimum FiniteLivedIntangibleAssetsUsefulLifeMinimum	1
CY2012	us-gaap	Finite Lived Intangible Assets Useful Life Maximum FiniteLivedIntangibleAssetsUsefulLifeMaximum	10
CY2012	ttek	Number Of Steps Involved In Process Of Goodwill Annual Impairment Test NumberOfStepsInvolvedInProcessOfGoodwillAnnualImpairmentTest	2	step
CY2012	ttek	Concentration Of Credit Risk Number Of Financial Institutions For Investment Exposure ConcentrationOfCreditRiskNumberOfFinancialInstitutionsForInvestmentExposure	1	entity
CY2012Q3	ttek	Percentage Of Account Receivables Due From Agencies PercentageOfAccountReceivablesDueFromAgencies	0.26	pure
CY2011Q4	ttek	Percentage Of Account Receivables Due From Agencies PercentageOfAccountReceivablesDueFromAgencies	0.32	pure
CY2011Q4	us-gaap	Billed Contract Receivables BilledContractReceivables	364779000	USD
CY2012Q3	us-gaap	Billed Contract Receivables BilledContractReceivables	362331000	USD
CY2011Q4	us-gaap	Unbilled Contracts Receivable UnbilledContractsReceivable	309091000	USD
CY2012Q3	us-gaap	Unbilled Contracts Receivable UnbilledContractsReceivable	355793000	USD
CY2011Q4	us-gaap	Contract Receivable Retainage ContractReceivableRetainage	15553000	USD
CY2012Q3	us-gaap	Contract Receivable Retainage ContractReceivableRetainage	17908000	USD
CY2011Q4	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	689423000	USD
CY2012Q3	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	736032000	USD
CY2011Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	32244000	USD
CY2012Q3	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	35552000	USD
CY2011Q4	us-gaap	Billings In Excess Of Cost Noncurrent BillingsInExcessOfCostNoncurrent	5832000	USD
CY2012Q3	us-gaap	Billings In Excess Of Cost Noncurrent BillingsInExcessOfCostNoncurrent	4410000	USD
CY2011Q4	us-gaap	Billings In Excess Of Cost BillingsInExcessOfCost	90586000	USD
CY2012Q3	us-gaap	Billings In Excess Of Cost BillingsInExcessOfCost	95319000	USD
CY2011Q4	ttek	Government Contract Receivable Unbilled Amounts Related To Claims And Requests For Equitable Adjustment On Contract GovernmentContractReceivableUnbilledAmountsRelatedToClaimsAndRequestsForEquitableAdjustmentOnContract	16000000	USD
CY2011Q4	ttek	Government Contract Receivable Billed Amounts GovernmentContractReceivableBilledAmounts	88500000	USD
CY2012Q3	ttek	Government Contract Receivable Billed Amounts GovernmentContractReceivableBilledAmounts	65900000	USD
CY2011Q4	us-gaap	Government Contract Receivable Unbilled Amounts GovernmentContractReceivableUnbilledAmounts	102700000	USD
CY2011	ttek	Concentration Of Risk Accounts Receivable Percentage Minimum ConcentrationOfRiskAccountsReceivablePercentageMinimum	0.10	pure
CY2012Q3	us-gaap	Government Contract Receivable Unbilled Amounts GovernmentContractReceivableUnbilledAmounts	100400000	USD
CY2012	ttek	Concentration Of Risk Accounts Receivable Percentage Minimum ConcentrationOfRiskAccountsReceivablePercentageMinimum	0.10	pure
CY2012Q3	ttek	Government Contract Receivable Unbilled Amounts Related To Claims And Requests For Equitable Adjustment On Contract GovernmentContractReceivableUnbilledAmountsRelatedToClaimsAndRequestsForEquitableAdjustmentOnContract	21000000	USD
CY2012Q3	ttek	Business Acquisition Contingent Consideration Potential Cash Payment Current BusinessAcquisitionContingentConsiderationPotentialCashPaymentCurrent	35400000	USD
CY2011Q4	ttek	Business Acquisition Contingent Consideration Potential Cash Payment Current BusinessAcquisitionContingentConsiderationPotentialCashPaymentCurrent	64100000	USD
CY2012Q3	ttek	Business Acquisition Contingent Consideration Potential Cash Payment Noncurrent BusinessAcquisitionContingentConsiderationPotentialCashPaymentNoncurrent	16100000	USD
CY2011Q4	ttek	Business Acquisition Contingent Consideration Potential Cash Payment Noncurrent BusinessAcquisitionContingentConsiderationPotentialCashPaymentNoncurrent	11000000	USD
CY2011Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	118141000	USD
CY2012	us-gaap	Depreciation Depreciation	26651000	USD
CY2010Q4	us-gaap	Goodwill Goodwill	394422000	USD
CY2011	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	160662000	USD
CY2011	us-gaap	Goodwill Translation Adjustments GoodwillTranslationAdjustments	-3486000	USD
CY2011	us-gaap	Goodwill Allocation Adjustment GoodwillAllocationAdjustment	17816000	USD
CY2012	us-gaap	Future Amortization Expense Year One FutureAmortizationExpenseYearOne	17834000	USD
CY2012	us-gaap	Future Amortization Expense Year Two FutureAmortizationExpenseYearTwo	14272000	USD
CY2012	us-gaap	Future Amortization Expense Year Three FutureAmortizationExpenseYearThree	13229000	USD
CY2012	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	38391000	USD
CY2012	us-gaap	Future Amortization Expense Year Four FutureAmortizationExpenseYearFour	11617000	USD
CY2012	us-gaap	Future Amortization Expense Year Five FutureAmortizationExpenseYearFive	9563000	USD
CY2012	us-gaap	Future Amortization Expense After Year Five FutureAmortizationExpenseAfterYearFive	7716000	USD
CY2012	us-gaap	Goodwill Translation Adjustments GoodwillTranslationAdjustments	18910000	USD
CY2012	us-gaap	Goodwill Allocation Adjustment GoodwillAllocationAdjustment	10157000	USD
CY2012Q3	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	167528000	USD
CY2011Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	142416000	USD
CY2012Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	93297000	USD
CY2011Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	61363000	USD
CY2012	us-gaap	Finite Lived Intangible Assets Amortization Expense FiniteLivedIntangibleAssetsAmortizationExpense	29600000	USD
CY2011	us-gaap	Finite Lived Intangible Assets Amortization Expense FiniteLivedIntangibleAssetsAmortizationExpense	28000000	USD
CY2010	us-gaap	Finite Lived Intangible Assets Amortization Expense FiniteLivedIntangibleAssetsAmortizationExpense	12700000	USD
CY2011Q3	ttek	Notional Amount Of Each New Foreign Currency Cash Flow Hedge Derivative NotionalAmountOfEachNewForeignCurrencyCashFlowHedgeDerivative	4200000	CAD
CY2012	us-gaap	Finite Lived Intangible Assets Future Amortization Expense FiniteLivedIntangibleAssetsFutureAmortizationExpense	74231000	USD
CY2012Q3	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	209427000	USD
CY2011Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	195677000	USD
CY2012Q3	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	135118000	USD
CY2011	us-gaap	Depreciation Depreciation	27138000	USD
CY2010	us-gaap	Depreciation Depreciation	20402000	USD
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	141035000	USD
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	126912000	USD
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	119729000	USD
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	19761000	USD
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	13580000	USD
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	3358000	USD
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	160796000	USD
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	140492000	USD
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	123087000	USD
CY2012	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	46058000	USD
CY2011	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	30246000	USD
CY2010	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	28538000	USD
CY2012	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	6949000	USD
CY2012	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	8569000	USD
CY2012	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	61576000	USD
CY2011	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	5948000	USD
CY2011	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	9596000	USD
CY2010	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	5489000	USD
CY2010	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	600000	USD
CY2010	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	34627000	USD
CY2011	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	45790000	USD
CY2012	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-200000	USD
CY2012	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-622000	USD
CY2012	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-4690000	USD
CY2011	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	6755000	USD
CY2011	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	1069000	USD
CY2011	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-6104000	USD
CY2010	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	9978000	USD
CY2010	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	1951000	USD
CY2010	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-288000	USD
CY2012	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	56278000	USD
CY2011	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	49172000	USD
CY2010	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	43080000	USD
CY2011	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	4376000	USD
CY2011	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	1689000	USD
CY2011	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-4140000	USD
CY2011	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	561000	USD
CY2010	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	4787000	USD
CY2010	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	400000	USD
CY2010	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-863000	USD
CY2010	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	-408000	USD
CY2012	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	4932000	USD
CY2012	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	360000	USD
CY2012	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-4444000	USD
CY2011	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2010	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2011	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.031	pure
CY2010	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.039	pure
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	-0.012	pure
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	-0.003	pure
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.007	pure
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.003	pure
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.030	pure
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.005	pure
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	-0.002	pure
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.028	pure
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.003	pure
CY2012	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350	pure
CY2012	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.031	pure
CY2012Q3	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	975000	USD
CY2012Q3	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	4689000	USD
CY2012Q3	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	2039000	USD
CY2012Q3	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	13298000	USD
CY2012Q3	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	10980000	USD
CY2012Q3	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	2926000	USD
CY2012Q3	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	32395000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	765000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	5271000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	5876000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	16974000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	10057000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	388000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	39331000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	47858000	USD
CY2011Q4	ttek	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	3950000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	26128000	USD
CY2011Q4	ttek	Deferred Tax Liabilities Cash To Accrual Adjustments DeferredTaxLiabilitiesCashToAccrualAdjustments	262000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	9397000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	87595000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	-48264000	USD
CY2012Q3	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	45417000	USD
CY2012Q3	ttek	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	2251000	USD
CY2012Q3	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	21695000	USD
CY2012Q3	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	8109000	USD
CY2012Q3	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	77472000	USD
CY2012Q3	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	-45077000	USD
CY2012	ttek	Undistributed Earnings Of Foreign Subsidiaries UndistributedEarningsOfForeignSubsidiaries	37000000	USD
CY2012Q3	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	18500000	USD
CY2012Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	24092000	USD
CY2010Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	21806000	USD
CY2009Q3	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	20530000	USD
CY2011Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	25940000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	6273000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	8007000	USD
CY2010	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	6895000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	19000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	2554000	USD
CY2010	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	2720000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	8072000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	6315000	USD
CY2010	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	5093000	USD
CY2012Q3	us-gaap	Loans Payable Current LoansPayableCurrent	500000	USD
CY2011Q4	us-gaap	Capital Lease Obligations CapitalLeaseObligations	1700000	USD
CY2012Q3	us-gaap	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments	2850000	USD
CY2012	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	6551000	USD
CY2011Q4	us-gaap	Loans Payable Current LoansPayableCurrent	1200000	USD
CY2012Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	848000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	68000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	112000	USD
CY2010	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	3246000	USD
CY2011Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	3200000	USD
CY2012Q3	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	3100000	USD
CY2011	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	6778000	USD
CY2010	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	6588000	USD
CY2012	ttek	Defined Benefit Plan Minimum Service Period For Eligibility DefinedBenefitPlanMinimumServicePeriodForEligibility	1
CY2012	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	14700000	USD
CY2011	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	14100000	USD
CY2010	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	13800000	USD
CY2012Q3	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	13400000	USD
CY2011Q4	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	11300000	USD
CY2011Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	147424000	USD
CY2012Q3	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	83078000	USD
CY2012Q3	us-gaap	Capital Lease Obligations CapitalLeaseObligations	2800000	USD
CY2012Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	2031000	USD
CY2012Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	601000	USD
CY2012Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	79598000	USD
CY2012	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	76600000	USD
CY2011	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	71900000	USD
CY2010	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	60900000	USD
CY2012Q3	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	68573000	USD
CY2012Q3	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	53595000	USD
CY2012Q3	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	37823000	USD
CY2012Q3	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	20340000	USD
CY2012Q3	us-gaap	Operating Leases Future Minimum Payments Due OperatingLeasesFutureMinimumPaymentsDue	198768000	USD
CY2012Q3	us-gaap	Capital Leases Future Minimum Payments Due In Two Years CapitalLeasesFutureMinimumPaymentsDueInTwoYears	1246000	USD
CY2012Q3	us-gaap	Capital Leases Future Minimum Payments Due In Four Years CapitalLeasesFutureMinimumPaymentsDueInFourYears	636000	USD
CY2012Q3	us-gaap	Capital Leases Future Minimum Payments Due In Three Years CapitalLeasesFutureMinimumPaymentsDueInThreeYears	836000	USD
CY2012Q3	us-gaap	Capital Leases Future Minimum Payments Due In Five Years CapitalLeasesFutureMinimumPaymentsDueInFiveYears	376000	USD
CY2012Q3	us-gaap	Capital Leases Future Minimum Payments Due CapitalLeasesFutureMinimumPaymentsDue	3094000	USD
CY2012Q3	us-gaap	Capital Leases Future Minimum Payments Interest Included In Payments CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments	244000	USD
CY2012Q3	us-gaap	Deferred Compensation Liability Classified Noncurrent DeferredCompensationLiabilityClassifiedNoncurrent	12900000	USD
CY2011Q4	us-gaap	Deferred Compensation Liability Classified Noncurrent DeferredCompensationLiabilityClassifiedNoncurrent	10600000	USD
CY2012	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	717000	shares
CY2011	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	722000	shares
CY2010	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	657000	shares
CY2010	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10178000	USD
CY2012	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4288000	USD
CY2011	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3804000	USD
CY2010	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3590000	USD
CY2012	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10839000	USD
CY2011	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10582000	USD
CY2012	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	1900000	shares
CY2011	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	2600000	shares
CY2010	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	3100000	shares
CY2012	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest	29000	USD
CY2011	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest	492000	USD
CY2012	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	381000	USD
CY2011	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	3435000	USD
CY2012	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	130643000	USD
CY2011	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	76030000	USD
CY2010	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	83356000	USD
CY2009Q4	ttek	Notional Amount Of Each New Foreign Currency Cash Flow Hedge Derivative NotionalAmountOfEachNewForeignCurrencyCashFlowHedgeDerivative	4200000	CAD
CY2009Q4	ttek	Notional Amount Of Each New Foreign Currency Cash Flow Hedge Derivative NotionalAmountOfEachNewForeignCurrencyCashFlowHedgeDerivative	4000000	USD
CY2010Q1	ttek	Notional Amount Of Each New Foreign Currency Cash Flow Hedge Derivative NotionalAmountOfEachNewForeignCurrencyCashFlowHedgeDerivative	4200000	CAD
CY2010Q1	ttek	Notional Amount Of Each New Foreign Currency Cash Flow Hedge Derivative NotionalAmountOfEachNewForeignCurrencyCashFlowHedgeDerivative	3900000	USD
CY2011Q3	ttek	Notional Amount Of Each New Foreign Currency Cash Flow Hedge Derivative NotionalAmountOfEachNewForeignCurrencyCashFlowHedgeDerivative	4200000	USD
CY2012Q2	us-gaap	Derivative Cash Received On Hedge DerivativeCashReceivedOnHedge	3900000	USD
CY2011Q4	us-gaap	Variable Interest Entity Nonconsolidated Carrying Amount Assets VariableInterestEntityNonconsolidatedCarryingAmountAssets	24000000	USD
CY2011Q4	us-gaap	Variable Interest Entity Nonconsolidated Carrying Amount Liabilities VariableInterestEntityNonconsolidatedCarryingAmountLiabilities	21000000	USD
CY2012Q1	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	682627000	USD
CY2012Q2	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	624345000	USD
CY2012Q3	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	684698000	USD
CY2012Q3	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	719405000	USD
CY2012Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	36093000	USD
CY2012Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	35543000	USD
CY2012Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	46261000	USD
CY2012Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	48470000	USD
CY2012Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	22610000	USD
CY2012Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	22284000	USD
CY2012Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	29054000	USD
CY2012Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	30432000	USD
CY2012Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.36
CY2012Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.35
CY2012Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.46
CY2012Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.48
CY2012Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.36
CY2012Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.35
CY2012Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.45
CY2012Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.47
CY2012Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	62433000	shares
CY2012Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	63072000	shares
CY2012Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	63387000	shares
CY2012Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	63623000	shares
CY2012Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	63068000	shares
CY2012Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	63817000	shares
CY2012Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	64179000	shares
CY2012Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	64396000	shares
CY2011Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.36
CY2011Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.28
CY2011Q3	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	673792000	USD
CY2011Q4	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	675662000	USD
CY2011Q1	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	611124000	USD
CY2011Q2	us-gaap	Sales Revenue Services Net SalesRevenueServicesNet	612566000	USD
CY2011Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	34325000	USD
CY2011Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	29256000	USD
CY2011Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	39408000	USD
CY2011Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	43433000	USD
CY2011Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	22301000	USD
CY2011Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	17500000	USD
CY2011Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	23839000	USD
CY2011Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	26399000	USD
CY2011Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.38
CY2011Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.42
CY2011Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.36
CY2011Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.28
CY2011Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.38
CY2011Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.42
CY2011Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	61665000	shares
CY2011Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	62121000	shares
CY2011Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	62203000	shares
CY2011Q4	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	62310000	shares
CY2011Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	62443000	shares
CY2011Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	62945000	shares
CY2011Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	62934000	shares
CY2011Q4	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	62864000	shares
CY2012	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2012	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2012Q1	dei	Entity Public Float EntityPublicFloat	1600000000	USD
CY2012Q3	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2011Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2012Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	63837000	shares
CY2011Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	62495000	shares
CY2012Q3	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2011Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2012	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.349	pure
CY2011	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.338	pure
CY2012	ttek	Estimated Earn Out Liabilities For Acquisitions During The Period EstimatedEarnOutLiabilitiesForAcquisitionsDuringThePeriod	18981000	USD
CY2012	ttek	Increase Decrease In Fair Value Of Contingent Consideration Reported In Interest Expense IncreaseDecreaseInFairValueOfContingentConsiderationReportedInInterestExpense	1374000	USD
CY2012	ttek	Increase Decrease In Fair Value Of Contingent Consideration Reported In Operating Income IncreaseDecreaseInFairValueOfContingentConsiderationReportedInOperatingIncome	-19246000	USD
CY2012	ttek	Foreign Currency Transaction And Translation Adjustment ForeignCurrencyTransactionAndTranslationAdjustment	3027000	USD
CY2011	ttek	Increase Decrease In Fair Value Of Contingent Consideration Reported In Interest Expense IncreaseDecreaseInFairValueOfContingentConsiderationReportedInInterestExpense	1612000	USD
CY2011	ttek	Increase Decrease In Fair Value Of Contingent Consideration Reported In Operating Income IncreaseDecreaseInFairValueOfContingentConsiderationReportedInOperatingIncome	-1755000	USD
CY2011	ttek	Foreign Currency Transaction And Translation Adjustment ForeignCurrencyTransactionAndTranslationAdjustment	-743000	USD
CY2010	ttek	Estimated Earn Out Liabilities For Acquisitions During The Period EstimatedEarnOutLiabilitiesForAcquisitionsDuringThePeriod	20708000	USD
CY2010	ttek	Increase Decrease In Fair Value Of Contingent Consideration Reported In Interest Expense IncreaseDecreaseInFairValueOfContingentConsiderationReportedInInterestExpense	156000	USD
CY2010	ttek	Increase Decrease In Fair Value Of Contingent Consideration Reported In Operating Income IncreaseDecreaseInFairValueOfContingentConsiderationReportedInOperatingIncome	-265000	USD
CY2010	ttek	Foreign Currency Transaction And Translation Adjustment ForeignCurrencyTransactionAndTranslationAdjustment	-95000	USD
CY2011Q4	ttek	Business Acquisition Contingent Consideration Potential Cash Payment Current And Noncurrent BusinessAcquisitionContingentConsiderationPotentialCashPaymentCurrentAndNoncurrent	75159000	USD
CY2012Q3	ttek	Business Acquisition Contingent Consideration Potential Cash Payment Current And Noncurrent BusinessAcquisitionContingentConsiderationPotentialCashPaymentCurrentAndNoncurrent	51539000	USD
CY2011Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	5000000	USD
CY2010Q4	ttek	Business Acquisition Contingent Consideration Potential Cash Payment Current And Noncurrent BusinessAcquisitionContingentConsiderationPotentialCashPaymentCurrentAndNoncurrent	20504000	USD
CY2012	ttek	Payments Of Earn Out Liabilities PaymentsOfEarnOutLiabilities	18055000	USD
CY2012Q3	us-gaap	Variable Interest Entity Nonconsolidated Carrying Amount Assets VariableInterestEntityNonconsolidatedCarryingAmountAssets	19000000	USD
CY2012Q3	us-gaap	Variable Interest Entity Nonconsolidated Carrying Amount Liabilities VariableInterestEntityNonconsolidatedCarryingAmountLiabilities	15700000	USD
CY2012	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	914000	USD
CY2012	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	19246000	USD
CY2011	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	1755000	USD
CY2010	ttek	Fair Value Adjustments To Contingent Consideration FairValueAdjustmentsToContingentConsideration	265000	USD
CY2012	ttek	Fair Value Adjustment To Assets Held For Sale FairValueAdjustmentToAssetsHeldForSale	3437000	USD
CY2010	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.376	pure

Files In Submission

Name	View Source	Status
0001047469-12-010616-index-headers.html	Edgar Link	pending
0001047469-12-010616-index.html	Edgar Link	pending
0001047469-12-010616.txt	Edgar Link	pending
0001047469-12-010616-xbrl.zip	Edgar Link	pending
a2211677z10-k.htm	Edgar Link	pending
a2211677zex-10_13.htm	Edgar Link	pending
a2211677zex-10_2.htm	Edgar Link	pending
a2211677zex-21.htm	Edgar Link	pending
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a2211677zex-31_1.htm	Edgar Link	pending
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a2211677zex-32_1.htm	Edgar Link	pending
a2211677zex-32_2.htm	Edgar Link	pending
a2211677zex-95.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xls	Edgar Link	pending
g191192kk01i001.jpg	Edgar Link	pending
g191192kk01i002.jpg	Edgar Link	pending
g191192kk01i003.gif	Edgar Link	pending
g191192kk03i001.jpg	Edgar Link	pending
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g191192kk03i005.jpg	Edgar Link	pending
g944492.jpg	Edgar Link	pending
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report.css	Edgar Link	pending
Show.js	Edgar Link	pending
ttek-20120930.xml	Edgar Link	completed
ttek-20120930.xsd	Edgar Link	pending
ttek-20120930_cal.xml	Edgar Link	unprocessable
ttek-20120930_def.xml	Edgar Link	unprocessable
ttek-20120930_lab.xml	Edgar Link	unprocessable
ttek-20120930_pre.xml	Edgar Link	unprocessable

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$TTEK
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2011 Q4 Form 10-K Financial Statement

#000104746912010616 Filed on November 15, 2012

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$TTEK TETRA TECH INC Stock $ttek

2011 Q4 Form 10-K Financial Statement

#000104746912010616 Filed on November 15, 2012

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$TTEK
TETRA TECH INC Stock $ttek