Derivatives (Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized loss on interest rate swaps		$ (25)	$ (159)	$ (1,300)	$ (1,264)
Reclassification of unrealized loss into earnings from dedesignated interest rate swaps (2)	[1]	(95)	0	(95)	0
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized loss on interest rate swaps		(25)	(159)	(1,300)	(1,264)
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from AOCIL on the effective portion into Income	[2]	(420)	(125)	(993)	(263)
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net		1,485		1,485
Not Designated as Hedging Instrument | Interest Rate Swap [Member] | Other Nonoperating Income (Expense)
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification of unrealized loss into earnings from dedesignated interest rate swaps (2)		$ (95)	$ 0	$ (95)	$ 0

[1] Amounts for dedesignated cash flow hedges reclassified from accumulated other comprehensive income (loss) to net income (loss) were included in other expense (income), net in the Company's Consolidated Condensed Statements of Operations.

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