Condensed Consolidated Income Statements Of Income and Comprehensive Income (Parenthetical) - USD ($)	3 Months Ended	9 Months Ended
Nov. 03, 2018	Oct. 28, 2017	Nov. 03, 2018	Oct. 28, 2017
OtherComprehensiveIncomeLossTaxParentheticalDisclosuresAbstract
Tax Effect of Unrealized Gains (Losses) On Available-For-Sale Securities	$ (117,000)	$ (101,000)	$ (141,000)	$ 272,000

Amount of tax expense (benefit) before reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e640-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration