Long-Term and Short-Term Financing Arrangements (Narrative) (Details) - USD ($) $ in Thousands					3 Months Ended		6 Months Ended
	Aug. 26, 2015	Jul. 27, 2015	Jul. 24, 2015	Dec. 18, 2014	Jul. 30, 2016	Aug. 01, 2015	Jul. 30, 2016	Aug. 01, 2015	May 11, 2011
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 600,000
Line of Credit Borrowing Capacity Increase Option				$ 150,000
Line of Credit Facility, Expiration Date				Dec. 18, 2019
Line of Credit Facility Percentage of Borrowing Base Under Condition One				12.50%
Number of consecutive business days for borrowing base availability over minimum under condition one				30 days
Line of Credit Facility Percentage of Borrowing Base Under Condition Two				10.00%
Line of Credit Facility Borrowing Base Availability Under Condition Two				$ 50,000
Line of Credit, Current					$ 0		$ 0
Letters of Credit Outstanding, Amount					6,500		6,500
Line of Credit Facility, Remaining Borrowing Capacity					593,500		593,500
Loss on early extinguishment of debt						$ (8,690)	0	$ (8,690)
Two Thousand Nineteen Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount									$ 200,000
Debt Instrument, Interest Rate, Stated Percentage									7.125%
Principal Amount Redeemed in Tender Offer	$ 39,300		$ 160,700
Debt Instrument, Redemption Price, Percentage	103.563%		103.95%
Loss on early extinguishment of debt					$ 0	$ (8,690)	$ 0	$ (8,690)
Two Thousand Twenty Three Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 200,000
Debt Instrument, Interest Rate, Stated Percentage		6.25%
Debt Instrument, Redemption Price, Percentage							101.00%
Proceeds from Issuance of Debt		$ 196,300
Debt Instrument, Maturity Date		Aug. 15, 2023