Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 29, 2016	Oct. 31, 2015	Oct. 29, 2016	Oct. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance Accumulated other comprehensive income, net of tax			$ 800
Unrealized gain on available-for-sale securities, net of deferred income taxes	$ (881)	$ 207	(269)	$ (27)
Ending Balance Accumulated other comprehensive income, net of tax	531		531
ChangeInUnrealizedGainsOnAvailableForSaleSecuritiesMember [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance Accumulated other comprehensive income, net of tax	1,412	552	800	786
Other Comprehensive Income Loss Before Reclassifications Net Of Tax	(765)	227	(101)	(154)
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	(116)	(20)	(168)	127
Unrealized gain on available-for-sale securities, net of deferred income taxes	(881)	207	(269)	(27)
Ending Balance Accumulated other comprehensive income, net of tax	$ 531	$ 759	$ 531	$ 759