Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Jan. 01, 2017	Dec. 27, 2015
Condensed Consolidated Statements of Income
Revenue	$ 668,851	$ 560,708
Subcontractor costs	(179,300)	(139,752)
Other costs of revenue	(408,190)	(347,796)
Gross profit	81,361	73,160
Selling, general and administrative expenses	(41,506)	(39,229)
Contingent consideration - fair value adjustments		(1,001)
Operating income	39,855	32,930
Interest expense, net	(2,908)	(1,660)
Income before income tax expense	36,947	31,270
Income tax expense	(10,358)	(8,030)
Net income including noncontrolling interests	26,589	23,240
Net income from noncontrolling interests	(27)	(1)
Net income attributable to Tetra Tech	$ 26,562	$ 23,239
Earnings per share attributable to Tetra Tech:
Basic (in dollars per share)	$ 0.47	$ 0.39
Diluted (in dollars per share)	$ 0.46	$ 0.39
Weighted-average common shares outstanding:
Basic (in shares)	57,099	59,058
Diluted (in shares)	58,145	59,793
Cash dividends paid per share	$ 0.09	$ 0.08