Summary of Significant Accounting Policies (Fair Value of Financial Instruments) (Details) - USD ($) $ in Thousands	Jul. 31, 2021	Jan. 30, 2021	Aug. 01, 2020
Significant Accounting Policies [Line Items]
Amortized Cost	$ 286,929	$ 140,928	$ 41,670
Gross Unrealized Gains	0	0	65
Gross Unrealized Losses	55	60	0
Fair Market Value	286,874	140,868	41,735
Other Long-term Investments
Significant Accounting Policies [Line Items]
Amortized Cost	1,104
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Fair Market Value	1,105
Fair Value, Inputs, Level 1
Significant Accounting Policies [Line Items]
Cash equivalents	73,900	250,700	144,100
Corporate bonds | Fair Value, Inputs, Level 2
Significant Accounting Policies [Line Items]
Amortized Cost	234,909	95,530	41,670
Gross Unrealized Gains	0	0	65
Gross Unrealized Losses	49	53	0
Fair Market Value	234,860	95,477	$ 41,735
Municipal bonds | Fair Value, Inputs, Level 2
Significant Accounting Policies [Line Items]
Amortized Cost	52,020	45,398
Gross Unrealized Gains	0	0
Gross Unrealized Losses	6	7
Fair Market Value	52,014	$ 45,391
Municipal bonds | Fair Value, Inputs, Level 2 | Other Long-term Investments
Significant Accounting Policies [Line Items]
Amortized Cost	1,104
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Fair Market Value	$ 1,105