Derivative Held for Hedging the Risk of Changes in Forecasted Interest Payments on Issuance of Long-term Debt (Details) - USD ($)					4 Months Ended
		Aug. 08, 2016	Aug. 05, 2016	Mar. 28, 2012	Apr. 21, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Fair Value Deferred in AOCI		$ 1,000,000	$ 1,000,000	$ 3,100,000
April/2012
Derivative Instruments, Gain (Loss) [Line Items]
Terminated					2012-04
Description					Treasury lock
Aggregate Notional Amount					$ 500,000,000
Fair Value When Terminated					(3,137,000)
Fair Value Deferred in AOCI	[1]				2,510,000
Ineffective Portion at Termination					$ 627,000
September/2016
Derivative Instruments, Gain (Loss) [Line Items]
Terminated					2016-09
Description					Treasury lock
Aggregate Notional Amount					$ 200,000,000
Fair Value When Terminated					1,298,000
Fair Value Deferred in AOCI	[1]				$ (1,298,000)
September/2016
Derivative Instruments, Gain (Loss) [Line Items]
Terminated					2016-09
Description					Treasury lock
Aggregate Notional Amount					$ 150,000,000
Fair Value When Terminated					(323,000)
Fair Value Deferred in AOCI	[1]				215,000
Ineffective Portion at Termination					$ 108,000

[1] The amount reported in AOCI is reclassified to interest expense as interest payments are made on the related notes through the maturity date.