Fair Value Measurements (Fair Value Measurements - Carrying Amount and Fair Value) (Details) - USD ($) $ in Thousands		Mar. 27, 2021	Dec. 26, 2020
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Finance lease obligations	[1]	$ 16,157	$ 16,938
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Cash and cash equivalents		1,523	1,920
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Long-term debt and finance leases, including current portion		59,859	61,219
Finance lease obligations		16,157	16,938
Interest rate swaps		368	440
Estimate of Fair Value, Fair Value Disclosure [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Cash and cash equivalents		1,523	1,920
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Long-term debt and finance leases, including current portion		57,961	58,803
Finance lease obligations		17,558	18,451
Interest rate swaps		$ 368	$ 440

[1] Includes leases classified as failed sale-leaseback transactions.