Fair Value Measurement - Securities Carried at Amortized Cost Plus Accrued Interest (Details) - USD ($) $ in Thousands	Aug. 03, 2019	Feb. 02, 2019
Investment securities classified as held to maturity
Amortized Cost	$ 54,752	$ 59,233
Fair Market Value	54,776	59,184
Short-term Investments
Investment securities classified as held to maturity
Amortized Cost	37,776	50,350
Gross Unrealized Gains	19	4
Gross Unrealized Losses	(1)	(37)
Fair Market Value	37,794	50,317
Short-term Investments \| Obligations of the U.S. Treasury \| Fair Value, Inputs, Level 1
Investment securities classified as held to maturity
Amortized Cost	30,630	38,706
Gross Unrealized Gains	19	4
Gross Unrealized Losses	(1)	(37)
Fair Market Value	30,648	38,673
Short-term Investments \| Obligations of states and municipalities \| Fair Value, Inputs, Level 2
Investment securities classified as held to maturity
Amortized Cost		95
Fair Market Value		95
Short-term Investments \| Bank certificates of deposit \| Fair Value, Inputs, Level 2
Investment securities classified as held to maturity
Amortized Cost	7,146	11,549
Fair Market Value	7,146	11,549
Long Term Investments
Investment securities classified as held to maturity
Amortized Cost	16,976	8,883
Gross Unrealized Gains	6
Gross Unrealized Losses		(16)
Fair Market Value	16,982	8,867
Long Term Investments \| Obligations of the U.S. Treasury \| Fair Value, Inputs, Level 1
Investment securities classified as held to maturity
Amortized Cost	2,485	4,956
Gross Unrealized Gains	6
Gross Unrealized Losses		(16)
Fair Market Value	2,491	4,940
Long Term Investments \| Bank certificates of deposit \| Fair Value, Inputs, Level 2
Investment securities classified as held to maturity
Amortized Cost	14,491	3,927
Fair Market Value	$ 14,491	$ 3,927

Amount of investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Section 50
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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

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-Name Accounting Standards Codification
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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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