Earnings per Share ("EPS") (Tables)

6 Months Ended

Apr. 01, 2018

Earnings Per Share [Abstract]

Schedule of number of weighted-average shares used to compute basic and diluted EPS

The following table sets forth the number of weighted-average shares used to compute basic and diluted EPS:

	Three Months Ended				Six Months Ended
	April 1, 2018		April 2, 2017		April 1, 2018		April 2, 2017
	(in thousands, except per share data)
Net income attributable to Tetra Tech	$	28,725	$	26,862	$	74,759	$	53,424
Weighted-average common shares outstanding – basic	55,841		57,270		55,900		57,171
Effect of dilutive stock options and unvested restricted stock	832		1,000		925		1,023
Weighted-average common stock outstanding – diluted	56,673		58,270		56,825		58,194
Earnings per share attributable to Tetra Tech:
Basic	$	0.51	$	0.47	$	1.34	$	0.93
Diluted	$	0.51	$	0.46	$	1.32	$	0.92