CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Jan. 30, 2021	Jan. 25, 2020	Jan. 26, 2019
Income Statement [Abstract]
Contract revenues	$ 3,199,165	$ 3,339,682	$ 3,127,700
Costs of earned revenues, excluding depreciation and amortization	2,641,989	2,779,730	2,562,392
General and administrative	259,770	254,590	269,140
Depreciation and amortization	175,897	187,556	179,603
Goodwill impairment charge	53,264	0	0
Total	3,130,920	3,221,876	3,011,135
Interest expense, net	(29,671)	(50,859)	(44,369)
Gain (loss) on debt extinguishment	12,046	(76)	0
Other income, net	8,597	11,665	15,842
Income before income taxes	59,217	78,536	88,038
Provision for income taxes	24,880	21,321	25,131
Net income	$ 34,337	$ 57,215	$ 62,907
Earnings per common share:
Basic earnings per common share (in dollars per share)	$ 1.08	$ 1.82	$ 2.01
Diluted earnings per common share (in dollars per share)	$ 1.07	$ 1.80	$ 1.97
Shares used in computing earnings per common share:
Basic (in shares)	31,665,183	31,498,474	31,250,376
Diluted (in shares)	32,090,578	31,821,782	31,990,168