Debt: (Details) - Revolving Credit Facility - Fourth Amended and Restated Credit Agreement	3 Months Ended	9 Months Ended
	Jul. 30, 2016 USD ($)	Oct. 29, 2016 USD ($)	May 24, 2016 USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 325,000,000
Anticipated write-off of deferred costs	$ 300,000
Amount of availability subject to threshold, number of consecutive days required		3 days
Amount of availability subject to threshold		$ 23,500,000.0
Percent of availability subject to threshold		10.00%
Fixed charge coverage ratio		1.0
Percent of availability subject to threshold, number of consecutive days		30 days