Summary of Significant Accounting Policies (Fair Value of Financial Instruments) (Details) - USD ($) $ in Thousands	Oct. 28, 2017	Jan. 28, 2017	Oct. 29, 2016
Significant Accounting Policies [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	$ 56,678	$ 77,791	$ 9,912
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	0	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	46	112	8
Held-to-maturity Securities, Fair Value	56,632	77,679	9,904
Fair Value, Inputs, Level 1 [Member]
Significant Accounting Policies [Line Items]
Cash equivalents	16,700	36,300	35,800
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Significant Accounting Policies [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	50,778	45,558	6,366
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	0	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	46	98	7
Held-to-maturity Securities, Fair Value	50,732	45,460	6,359
Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Significant Accounting Policies [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	5,900	32,233	3,546
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	14	1
Held-to-maturity Securities, Fair Value	5,900	32,219	$ 3,545
Other Long-term Investments [Member]
Significant Accounting Policies [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	23,177	10,514
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	0	8
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	98	11
Held-to-maturity Securities, Fair Value	23,079	11
Other Long-term Investments [Member] | Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Significant Accounting Policies [Line Items]
Held-to-maturity Securities, Fair Value	23,079	6
Other Long-term Investments [Member] | Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Significant Accounting Policies [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	23,177	6,265
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	$ 98	11
Other Long-term Investments [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Significant Accounting Policies [Line Items]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment		4,249
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain		8
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss		0
Held-to-maturity Securities, Fair Value		$ 4,257