Leases - Lease Cost and Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 25, 2020	Apr. 27, 2019	Jan. 25, 2020
Leases [Abstract]
Lease cost under long-term operating leases	$ 8,813	$ 8,331
Lease cost under short-term operating leases	8,833	8,406
Variable lease cost under short-term and long-term operating leases	1,132	1,210
Total lease cost	$ 18,778	$ 17,947
Operating Lease, Weighted Average Remaining Lease Term	3 years 4 months 24 days		3 years 3 months 18 days
Weighted average discount rate (percent)	5.10%		5.20%