Borrowings and Credit Facilities (Textuals) (Details) - USD ($)				1 Months Ended	3 Months Ended					9 Months Ended
	Dec. 14, 2015	Jul. 29, 2014	Oct. 12, 2011	Nov. 30, 2006	Apr. 27, 2018	Oct. 28, 2016	Jul. 29, 2016	Apr. 29, 2016	Jul. 31, 2015	Jul. 29, 2016	Jul. 31, 2015	Oct. 30, 2015	Jun. 16, 2011
Line of Credit Facility [Line Items]
Interest expense recognized for direct borrowings under the Credit Agreement							$ 12,291,000		$ 16,219,000	$ 37,651,000	$ 48,368,000
Repayments of Term Loan										(18,750,000)	0
Contractual Payment [Member]
Line of Credit Facility [Line Items]
Repayments of Term Loan										$ (18,800,000)
Term Loan due 2019
Line of Credit Facility [Line Items]
Principal amount		$ 375,000,000
Term loan outstanding		375,000,000
Repayments of Term Loan							$ 0
Term Loan due 2019 | Prepayment
Line of Credit Facility [Line Items]
Repayments of Term Loan								$ (9,400,000)
Prior Term Loan
Line of Credit Facility [Line Items]
Principal amount													$ 500,000,000.0
5.125% Senior Notes due 2021
Line of Credit Facility [Line Items]
Principal amount			$ 500,000,000.0
Interest rate (as percent)			5.125%				5.125%			5.125%		5.125%
Percentage of principal amount of notes to be redeemed at company's option (as percent)			100.00%
6.625% Senior Notes due 2036
Line of Credit Facility [Line Items]
Principal amount				$ 150,000,000.0
Interest rate (as percent)				6.625%			6.625%			6.625%		6.625%
Percentage of principal amount of notes to be redeemed at company's option (as percent)				100.00%
Treasury Rate | 5.125% Senior Notes due 2021
Line of Credit Facility [Line Items]
Basis spread on variable rate (as percent)			0.50%
Treasury Rate | 6.625% Senior Notes due 2036
Line of Credit Facility [Line Items]
Basis spread on variable rate (as percent)				0.375%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum consolidated leverage ratio		3.00					$ 4.25	$ 3.50
Unsecured revolving credit facility (Credit Agreement) maximum borrowing capacity	$ 850,000,000.000	1,000,000,000.0
Letter of credit sublimit	$ 500,000,000
Priority debt limit as a percentage of consolidated net worth (as percent)	10.00%
Cash dividend covenant limit	$ 25,000,000.0
Line of credit additional borrowing capacity		$ 250,000,000
Line of credit amount outstanding							0			$ 0
Interest expense recognized for direct borrowings under the Credit Agreement							100,000		$ 400,000	500,000	$ 900,000
Letters of credit outstanding							110,900,000			110,900,000
Available borrowing capacity							$ 739,100,000			$ 739,100,000
Revolving Credit Facility | Eurodollar Interest Period One
Line of Credit Facility [Line Items]
Interest period		7 days
Revolving Credit Facility | Eurodollar Interest Period Two
Line of Credit Facility [Line Items]
Interest period		1 month
Revolving Credit Facility | Eurodollar Interest Period Three
Line of Credit Facility [Line Items]
Interest period		2 months
Revolving Credit Facility | Eurodollar Interest Period Four
Line of Credit Facility [Line Items]
Interest period		3 months
Revolving Credit Facility | Eurodollar Interest Period Five
Line of Credit Facility [Line Items]
Interest period		6 months
Revolving Credit Facility | Eurodollar Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (as percent)		1.00%
Revolving Credit Facility | Federal Funds Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (as percent)		0.50%
Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Line of credit commitment fee percentage on unused capacity (as percent)		0.09%
Revolving Credit Facility | Minimum | Eurodollar Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (as percent)		1.00%
Revolving Credit Facility | Maximum
Line of Credit Facility [Line Items]
Line of credit commitment fee percentage on unused capacity (as percent)		0.30%
Revolving Credit Facility | Maximum | Eurodollar Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (as percent)		2.00%
Forecast | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum consolidated leverage ratio					$ 3.0	$ 4.5