Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 26, 2020	Jan. 27, 2019	Jan. 28, 2018
Accounting Policies [Abstract]
Aggregate net investments under cost method of accounting	$ 19,400	$ 16,700
Total equity method investments	3,300	2,700
Impairment of investments	$ (1,211)	(30,000)	$ (4,250)
Percent of realizable undiscounted cash flows used to determine useful life of acquired finite-lived intangible assets, minimum	90.00%
Advertising costs	$ 900	600	600
Recoveries from nonrecurring engineering services	$ 8,400	$ 4,400	$ 5,400