CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 30, 2021	Oct. 24, 2020	Oct. 30, 2021	Oct. 24, 2020
Income Statement [Abstract]
Contract revenues	$ 853,973	$ 810,256	$ 2,369,038	$ 2,448,500
Costs of earned revenues, excluding depreciation and amortization	705,865	658,355	1,977,243	1,996,514
General and administrative	66,899	62,628	198,640	195,871
Depreciation and amortization	37,766	42,313	115,307	132,313
Goodwill impairment charge			0	53,264
Total	810,530	763,296	2,291,190	2,377,962
Interest expense, net	(9,132)	(4,710)	(24,343)	(25,020)
Other income, net	564	3,708	4,267	7,921
Income before income taxes	34,875	45,958	57,710	65,485
Provision for income taxes	6,158	12,032	9,930	26,953
Net income	$ 28,717	$ 33,926	$ 47,780	$ 38,532
Earnings per common share:
Basic earnings per common share (in dollars per share)	$ 0.95	$ 1.06	$ 1.57	$ 1.21
Diluted earnings per common share (in dollars per share)	$ 0.94	$ 1.05	$ 1.54	$ 1.20
Shares used in computing earnings per common share:
Basic (in shares)	30,172,254	31,878,583	30,426,337	31,744,199
Diluted (in shares)	30,614,706	32,425,300	30,928,890	32,106,661