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The low end of the range of percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	ttek_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange
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Data Type:	num:percentItemType
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Period Type:	duration

Represents the percentage margin added to the rate used to calculate the reference rate for the variable interest on the debt instrument.

No definition available.

Name:	ttek_DebtInstrumentMarginPercentageAddedToVariableRateBasis
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Data Type:	num:percentItemType
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Period Type:	instant

Represents the expected term of the debt instrument.

No definition available.

Name:	ttek_DebtInstrumentTerm
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Represents the calculated rate of interest, for a debt instrument with a variable interest rate, at the time of inception.

No definition available.

Name:	ttek_DebtInstrumentVariableInterestRateAtInception
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Data Type:	num:percentItemType
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Represents the ratio of consolidated earnings before, interest, taxes, depreciation and amortization minus capital expenditures to cash interest plus taxes plus principal payments of indebtedness including capital leases, notes and post-acquisition payments allowed under the terms of amended credit agreement's covenants.

No definition available.

Name:	ttek_LineOfCreditFacilityCovenantConsolidatedFixedChargeCoverageRatio
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Data Type:	xbrli:pureItemType
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Period Type:	instant

Represents the ratio of consolidated total debt to consolidated adjusted earnings before, interest, taxes, depreciation and amortization allowed under the terms of amended credit agreement's covenants.

No definition available.

Name:	ttek_LineOfCreditFacilityCovenantConsolidatedLeverageRatio
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Data Type:	xbrli:pureItemType
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Represents the capacity currently available under the credit facility for borrowings without the violation of debt covenants.

No definition available.

Name:	ttek_LineOfCreditFacilityRemainingBorrowingCapacityWithoutViolationOfDebtCovenants
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents term of revolving of credit facility in years.

No definition available.

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Data Type:	xbrli:durationItemType
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The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

No definition available.

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Data Type:	xbrli:stringItemType
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- Details

Name:	us-gaap_DebtInstrumentLineItems
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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20, 22

-Article 5

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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the next rolling twelve months following the latest balance sheet presented.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the fifth rolling twelve months following the latest balance sheet presented.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the fourth rolling twelve months following the latest balance sheet presented.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the third rolling twelve months following the latest balance sheet presented.

No definition available.

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInRollingYearThree
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Data Type:	xbrli:monetaryItemType
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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the second rolling twelve months following the latest balance sheet presented.

No definition available.