Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 29, 2015	Sep. 28, 2014
Current assets:
Cash and cash equivalents	$ 98,518	$ 122,379
Accounts receivable - net	666,013	701,892
Prepaid expenses and other current assets	48,657	52,256
Income taxes receivable	18,392	22,076
Total current assets	831,580	898,603
Property and equipment - net	65,107	73,864
Investments in and advances to unconsolidated joint ventures	2,159	2,140
Goodwill	671,397	714,190
Intangible assets - net	49,062	63,095
Other long-term assets	24,642	24,512
Total assets	1,643,947	1,776,404
Current liabilities:
Accounts payable	136,319	175,952
Accrued compensation	89,423	110,186
Billings in excess of costs on uncompleted contracts	95,270	103,343
Deferred income taxes	21,778	20,387
Current portion of long-term debt	10,805	10,989
Estimated contingent earn-out liabilities		3,568
Other current liabilities	73,499	79,436
Total current liabilities	427,094	503,861
Deferred income taxes	27,287	28,786
Long-term debt	228,007	192,842
Long-term estimated contingent earn-out liabilities		3,462
Other long-term liabilities	38,655	34,397
Commitments and contingencies
Equity:
Preferred stock - Authorized, 2,000 shares of $0.01 par value; no shares issued and outstanding at March 29, 2015, and September 28, 2014
Common stock - Authorized, 150,000 shares of $0.01 par value; issued and outstanding, 60,333 and 62,591 shares at March 29, 2015, and September 28, 2014, respectively	603	626
Additional paid-in capital	346,863	402,516
Accumulated other comprehensive loss	(112,620)	(42,538)
Retained earnings	687,437	651,475
Tetra Tech stockholders' equity	922,283	1,012,079
Noncontrolling interests	621	977
Total equity	922,904	1,013,056
Total liabilities and equity	$ 1,643,947	$ 1,776,404