Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 30, 2012	Sep. 30, 2012
CURRENT ASSETS:
Cash and cash equivalents	$ 151,604	$ 104,848
Accounts receivable - net	674,894	700,480
Prepaid expenses and other current assets	48,521	48,168
Income taxes receivable	18,869	5,817
Total current assets	893,888	859,313
PROPERTY AND EQUIPMENT - NET	71,591	74,309
INVESTMENTS IN AND ADVANCES TO UNCONSOLIDATED JOINT VENTURES	2,959	3,279
GOODWILL	644,149	635,958
INTANGIBLE ASSETS - NET	78,690	74,231
OTHER ASSETS	23,698	23,940
TOTAL ASSETS	1,714,975	1,671,030
CURRENT LIABILITIES:
Accounts payable	131,354	154,003
Accrued compensation	104,391	128,086
Billings in excess of costs on uncompleted contracts	94,511	90,909
Deferred income taxes	18,965	20,809
Current portion of long-term debt	1,856	2,031
Estimated contingent earn-out liabilities	20,089	35,407
Other current liabilities	66,698	72,549
Total current liabilities	437,864	503,794
DEFERRED INCOME TAXES	33,883	24,268
LONG-TERM DEBT	147,808	81,047
OTHER LONG-TERM LIABILITIES	44,214	42,054
COMMITMENTS AND CONTINGENCIES
EQUITY:
Preferred stock - Authorized, 2,000 shares of $0.01 par value; no shares issued and outstanding at December 30, 2012, and September 30, 2012
Common stock - Authorized, 150,000 shares of $0.01 par value; issued and outstanding, 64,374 and 63,837 shares at December 30, 2012, and September 30, 2012, respectively	644	638
Additional paid-in capital	443,437	433,009
Accumulated other comprehensive income	25,539	31,017
Retained earnings	580,530	554,306
Tetra Tech stockholders' equity	1,050,150	1,018,970
Noncontrolling interests	1,056	897
TOTAL EQUITY	1,051,206	1,019,867
TOTAL LIABILITIES AND EQUITY	$ 1,714,975	$ 1,671,030