Other Fair Value Measurements (Details) In Millions, unless otherwise specified	3 Months Ended
Apr. 01, 2012 USD ($)	Jul. 03, 2011 USD ($)	Jul. 03, 2011 CAD	Mar. 28, 2010 USD ($)	Mar. 28, 2010 CAD	Dec. 27, 2009 USD ($)	Dec. 27, 2009 CAD
Other Fair Value Measurements
Notional amount of each new foreign currency forward contract		$ 4.2	4.2	$ 3.9	4.2	$ 4.0	4.2
Settlement amount of the foreign currency forward contract	$ 3.9

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

No definition available.

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