Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 29, 2014	Sep. 29, 2013
Current assets:
Cash and cash equivalents	$ 188,872	$ 129,305
Accounts receivable - net	674,447	660,847
Prepaid expenses and other current assets	49,939	61,446
Income taxes receivable	17,570	20,044
Total current assets	930,828	871,642
Property and equipment - net	78,208	88,026
Investments in and advances to unconsolidated joint ventures	1,938	2,198
Goodwill	722,583	722,792
Intangible assets - net	66,115	86,929
Other long-term assets	24,548	27,505
Total assets	1,824,220	1,799,092
Current liabilities:
Accounts payable	173,024	142,813
Accrued compensation	115,730	114,810
Billings in excess of costs on uncompleted contracts	79,160	79,507
Deferred income taxes	25,120	18,170
Current portion of long-term debt	8,441	4,311
Estimated contingent earn-out liabilities	8,673	23,281
Other current liabilities	68,031	100,241
Total current liabilities	478,179	483,133
Deferred income taxes	26,480	30,525
Long-term debt	195,501	203,438
Long-term estimated contingent earn-out liabilities	22,830	58,508
Other long-term liabilities	35,069	24,685
Commitments and contingencies
Equity:
Preferred stock - Authorized, 2,000 shares of $0.01 par value; no shares issued and outstanding at June 29, 2014, and September 29, 2013
Common stock - Authorized, 150,000 shares of $0.01 par value; issued and outstanding, 64,348 and 64,134 shares at June 29, 2014, and September 29, 2013, respectively	643	641
Additional paid-in capital	447,864	443,099
Accumulated other comprehensive (loss) income	(16,588)	1,858
Retained earnings	633,339	552,165
Tetra Tech stockholders' equity	1,065,258	997,763
Noncontrolling interests	903	1,040
Total equity	1,066,161	998,803
Total liabilities and equity	$ 1,824,220	$ 1,799,092