Fair Value Measurement - Amortized Cost and Fair Market Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jul. 29, 2017	Jan. 28, 2017
Amortized Cost
Mature in one year or less	$ 32,669	$ 38,026
Mature after one year through five years	26,748	26,691
Total	59,417	64,717
Fair Market Value
Mature in one year or less	32,658	38,028
Mature after one year through five years	26,693	26,640
Total Fair Market Value	59,351	$ 64,668
Changes among the fair value levels
Changes between Level 1 to Level 2, Assets	$ 0

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

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-Name Accounting Standards Codification
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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of held-to-maturity debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, maturing in the next fiscal year through the fifth fiscal year following the latest fiscal year.

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Fair value of held-to-maturity debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of investments in debt securities classified as held-to-maturity.

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