Senior Credit Facility - Credit Agreement (Details) - USD ($)						1 Months Ended	3 Months Ended
	Feb. 19, 2021	Mar. 31, 2016	Mar. 26, 2016	Dec. 26, 2015	Mar. 28, 2015	Mar. 26, 2016	Mar. 26, 2016	Feb. 19, 2016
Line of Credit Facility [Line Items]
Senior credit facility, maximum borrowing capacity			$ 500,000,000			$ 500,000,000	$ 500,000,000
Swingline Loan, Maximum Borrowing Capacity			50,000,000
Debt Issuance Costs, Gross			1,400,000			1,400,000	1,400,000
Term Loan, Maximum Borrowing Capacity			$ 200,000,000			200,000,000
Debt Instrument, Maturity Date			Feb. 19, 2021
Purchase Obligation, Due in Next Twelve Months			$ 0			0	0
Letters of Credit Outstanding, Amount			$ 47,600,000	$ 48,700,000	$ 50,500,000	$ 47,600,000	$ 47,600,000
Debt instrument, basis spread on variable rate			0.63%
Commitment fee for unused capacity			0.10%
Base Rate
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Description			0.0350				bank’s base rate 3.25%
London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Description			.00435				LIBOR plus 0.19%
Minimum
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate						0.50%
Commitment fee for unused capacity						0.075%
Maximum
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate						1.125%
Commitment fee for unused capacity						0.20%
Senior credit facility [Member]
Line of Credit Facility [Line Items]
Senior credit facility, maximum borrowing capacity								$ 400,000,000
Swingline loan [Member]
Line of Credit Facility [Line Items]
Swing loan maximum borrowing capacity								$ 30,000,000
2016 Senior Credit Facility [Member]
Line of Credit Facility [Line Items]
Term loan, Maximum Month End Outstanding Amount			$ 200,000,000			$ 200,000,000	$ 200,000,000
Number of Financial Covenants [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Covenant Description						2
2011 Senior Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Month-end Outstanding Amount				$ 150,000,000	$ 60,000,000
2016 Senior Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Month-end Outstanding Amount			50,000,000
Unsecured Debt			250,000,000			$ 250,000,000	250,000,000
Compensating Balance, Amount			$ 0			$ 0	$ 0
Debt Instrument, Covenant Compliance			all
Due in years one and two [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Frequency of Periodic Payment						10
Due in years three through five [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Frequency of Periodic Payment						20
Fixed Charge Coverage Ratio Minimum Requirement [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Covenant Description			2.00
Leverage Ratio Maximum Requirement [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Covenant Description			4.00
Interest Rate Swap [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Maturity Date Range, Start		Mar. 31, 2016
Debt Instrument, Maturity Date Range, End	Feb. 19, 2021
Derivative, Notional Amount		$ 197,500,000