Fair Value Measurements (Details) In Millions, unless otherwise specified	3 Months Ended
Jul. 03, 2011 USD ($)	Apr. 03, 2011 USD ($)	Mar. 28, 2010 USD ($)	Mar. 28, 2010 CAD	Dec. 27, 2009 USD ($) contract	Dec. 27, 2009 CAD contract
Fair Value Measurements
Number of foreign currency forward contracts					3	3
Period over which foreign currency forward contracts fix interest income	three-year period				three annual periods	three annual periods
Number of foreign currency derivatives maturing annually (in contracts)					1	1
Notional amount of each new foreign currency forward contract	$ 4.2		$ 3.9	4.2	$ 4.0	4.2
Settlement amount of the foreign currency forward contract		$ 3.9	$ 3.9

Notional amount of each foreign currency derivative designated as a hedging instrument in a cash flow hedge entered into during the period.

Name:	ttek_NotionalAmountOfEachNewForeignCurrencyCashFlowHedgeDerivative
Namespace Prefix:	ttek
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the number of foreign currency derivatives maturing at the end of each annual period.

+ Details

Name:	ttek_NumberOfForeignCurrencyDerivativesMaturingPerAnnualPeriod
Namespace Prefix:	ttek
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of cash received during the period on settlement of a hedge.

+ Details

Name:	us-gaap_DerivativeCashReceivedOnHedge
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_FairValueDisclosuresAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80748-113994

+ Details

Name:	us-gaap_MaximumLengthOfTimeHedgedInForeignCurrencyCashFlowHedge
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of foreign currency exchange rate derivatives held by the entity at the reporting date.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44

-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 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5580258-113959

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579245-113959

+ Details

Name:	us-gaap_NumberOfForeignCurrencyDerivativesHeld
Namespace Prefix:	us-gaap
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant