Summary of Significant Accounting Policies (Fair Value of Financial Instruments) (Details) - USD ($)
$ in Thousands |
May 05, 2018 |
Feb. 03, 2018 |
Apr. 29, 2017 |
| Significant Accounting Policies [Line Items] |
|
|
|
| Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment |
$ 189,804
|
$ 131,958
|
$ 113,775
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Gain |
0
|
0
|
0
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Loss |
516
|
177
|
57
|
| Held-to-maturity Securities, Fair Value |
189,288
|
131,781
|
113,718
|
| Fair Value, Inputs, Level 1 [Member] |
|
|
|
| Significant Accounting Policies [Line Items] |
|
|
|
| Cash equivalents |
60,400
|
91,200
|
21,600
|
| 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 |
177,966
|
117,373
|
65,840
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Gain |
0
|
0
|
0
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Loss |
505
|
177
|
49
|
| Held-to-maturity Securities, Fair Value |
177,461
|
117,196
|
65,791
|
| 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 |
11,838
|
14,585
|
47,935
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Gain |
0
|
0
|
0
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Loss |
11
|
0
|
8
|
| Held-to-maturity Securities, Fair Value |
11,827
|
14,585
|
47,927
|
| Other Long-term Investments [Member] |
|
|
|
| Significant Accounting Policies [Line Items] |
|
|
|
| Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment |
2,930
|
27,702
|
6,669
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Gain |
0
|
0
|
7
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Loss |
14
|
172
|
2
|
| Held-to-maturity Securities, Fair Value |
2,916
|
27,530
|
6,674
|
| 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 |
850
|
25,295
|
3,886
|
| 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 |
856
|
25,465
|
3,888
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Gain |
0
|
0
|
0
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Loss |
6
|
170
|
2
|
| 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 |
2,074
|
2,237
|
2,781
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Gain |
0
|
0
|
7
|
| Held-to-maturity Securities, Accumulated Unrecognized Holding Loss |
8
|
2
|
0
|
| Held-to-maturity Securities, Fair Value |
$ 2,066
|
$ 2,235
|
$ 2,788
|