Significant Accounting Policies - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 26, 2020	Oct. 27, 2019	Jul. 28, 2019	Apr. 28, 2019	Jan. 27, 2019	Oct. 28, 2018	Jul. 29, 2018	Apr. 29, 2018	Jan. 26, 2020	Jan. 27, 2019	Jan. 28, 2018
Earnings Per Share, Basic and Diluted [Abstract]
Net income attributable to common shareholders	$ 2,934	$ 13,997	$ 2,192	$ 12,748	$ 13,843	$ 14,787	$ 27,260	$ 13,749	$ 31,871	$ 69,639	$ 34,649
Weighted average common shares outstanding–basic	66,041,000	66,387,000	66,519,000	66,105,000	65,525,000	66,014,000	66,063,000	66,324,000	66,263,000	65,982,000	66,027,000
Dilutive effect of share-based compensation									1,155,000	2,499,000	1,578,000
Weighted average common shares outstanding–diluted	67,051,000	67,318,000	67,746,000	67,976,000	68,165,000	68,731,000	68,880,000	68,195,000	67,418,000	68,481,000	67,605,000
Basic earnings (loss) per common share (in dollars per share)	$ 0.04	$ 0.21	$ 0.03	$ 0.19	$ 0.21	$ 0.22	$ 0.41	$ 0.21	$ 0.48	$ 1.06	$ 0.52
Diluted earnings (loss) per common share (in dollars per share)	$ 0.04	$ 0.21	$ 0.03	$ 0.19	$ 0.20	$ 0.22	$ 0.40	$ 0.20	$ 0.47	$ 1.02	$ 0.51
Anti-dilutive shares not included in the above calculations									120,000	553,000	402,000