v3.8.0.1
Investments - Summary of Investments Gross Unrealized Losses and Fair Value (Details) - USD ($)
$ in Thousands
May 05, 2018
Feb. 03, 2018
Fair Value    
Less than 12 months $ 346,612 $ 445,516
12 months or more 88,688 103,298
Total 435,300 548,814
Unrealized Loss    
Less than 12 months (2,038) (1,964)
12 months or more (852) (879)
Total (2,890) (2,843)
U.S. government and agency debt    
Fair Value    
Less than 12 months 123,181 148,538
12 months or more 45,137 51,332
Total 168,318 199,870
Unrealized Loss    
Less than 12 months (219) (298)
12 months or more (302) (346)
Total (521) (644)
Foreign government and agency debt    
Fair Value    
Less than 12 months 0 3,993
12 months or more 1,796 2,994
Total 1,796 6,987
Unrealized Loss    
Less than 12 months 0 (1)
12 months or more (13) (16)
Total (13) (17)
Municipal debt securities    
Fair Value    
Less than 12 months 1,314 1,969
12 months or more 0 0
Total 1,314 1,969
Unrealized Loss    
Less than 12 months (1) (6)
12 months or more 0 0
Total (1) (6)
Corporate debt securities    
Fair Value    
Less than 12 months 195,971 253,380
12 months or more 39,594 46,805
Total 235,565 300,185
Unrealized Loss    
Less than 12 months (1,660) (1,514)
12 months or more (498) (485)
Total (2,158) (1,999)
Asset backed securities    
Fair Value    
Less than 12 months 26,146 37,636
12 months or more 2,161 2,167
Total 28,307 39,803
Unrealized Loss    
Less than 12 months (158) (145)
12 months or more (39) (32)
Total $ (197) $ (177)