Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 27, 2018	Dec. 27, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, net		$ (1,800)
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, assets		10,838	$ 10,476
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, assets		12,679	12,663
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, liabilities		(1,841)	(2,187)
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, assets		0	0
Recurring [Member] | Deferred Compensation Plan Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan investments	[1]	$ 12,679	$ 12,663
Valuation technique		market approach	market approach
Recurring [Member] | Deferred Compensation Plan Investments [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan investments	[1]	$ 12,679	$ 12,663
Recurring [Member] | Deferred Compensation Plan Investments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan investments	[1]	0	0
Recurring [Member] | Deferred Compensation Plan Investments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan investments	[1]	0	0
Recurring [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, net	[2]	$ (1,841)	$ (2,187)
Valuation technique		income approach	income approach
Recurring [Member] | Interest Rate Swap [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, net	[2]	$ 0	$ 0
Recurring [Member] | Interest Rate Swap [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, net	[2]	(1,841)	(2,187)
Recurring [Member] | Interest Rate Swap [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, net	[2]	$ 0	$ 0

[1] The fair values of our deferred compensation plan investments are based on the closing market prices of the elected investments.

[2] The fair values of our interest rate swaps are based upon Level 2 inputs, which include valuation models as reported by our counterparties. The key inputs for the valuation models are quoted market prices, interest rates and forward yield curves. See Note 9 for details on the interest rate swaps.