Earnings per Share ("EPS") (Tables)

9 Months Ended

Jun. 28, 2020

Earnings Per Share [Abstract]

Schedule of Number of Weighted-average Shares Used to Compute Basic and Diluted EPS

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

	Three Months Ended				Nine Months Ended
	June 28, 2020		June 30, 2019		June 28, 2020		June 30, 2019
	(in thousands, except per share data)
Net income attributable to Tetra Tech	$	45,497	$	49,233	$	129,205	$	147,141
Weighted-average common shares outstanding – basic	53,985		54,819		54,366		55,101
Effect of dilutive stock options and unvested restricted stock	707		949		795		933
Weighted-average common shares outstanding – diluted	54,692		55,768		55,161		56,034
Earnings per share attributable to Tetra Tech:
Basic	$	0.84	$	0.90	$	2.38	$	2.67
Diluted	$	0.83	$	0.88	$	2.34	$	2.63