Derivatives (Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance) (Details) - Designated as Hedging Instrument [Member] - Interest Rate Swap [Member] - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 24, 2016	Sep. 30, 2017	Sep. 24, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in AOCIL on the effective portion of the Derivative		$ (57)	$ 24	$ (360)	$ (2,648)
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from AOCIL on the effective portion into Income	[1],[2]	(288)	(308)	(970)	(891)
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net		1,026		1,026
Other Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized on the ineffective portion in Income on interest rate swaps		$ 0	$ 0	$ 0	$ 0

[1] The amount of gain (loss) reclassified from AOCIL is included in interest expense on the Company's financial statements.

[2] The amount of loss expected to be reclassified from AOCIL into earnings during the next 12 months subsequent to September 30, 2017 is $1,026.