Leases - Lease Cost and Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 25, 2020	Jul. 27, 2019	Jul. 25, 2020	Jul. 27, 2019	Jan. 25, 2020
Leases [Abstract]
Lease cost under long-term operating leases	$ 8,763	$ 8,292	$ 17,615	$ 16,712
Lease cost under short-term operating leases	7,153	8,608	15,984	16,994
Variable lease cost under short-term and long-term operating leases	1,066	1,131	2,160	2,272
Total lease cost	$ 16,982	$ 18,031	$ 35,759	$ 35,978
Operating Lease, Weighted Average Remaining Lease Term	3 years 4 months 24 days		3 years 4 months 24 days		3 years 3 months 18 days
Weighted average discount rate (percent)	5.00%		5.00%		5.20%