General (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 29, 2018		Mar. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning Balance, Interest Rate Swaps		$ 0
Other comprehensive loss before reclassifications, Interest Rate Swaps		(170)		$ 0
Amounts reclassified from accumulated other comprehensive loss, Interest Rate Swaps		26	[1]	0
Net other comprehensive income (loss), Interest Rate Swaps		(144)
Ending Balance, Interest Rate Swaps		(144)
Beginning Balance, Available for Sale Investments		(11)		3
Change in unrealized gain on available for sale investments, Available for Sale Investments		0		(14)
Other comprehensive loss before reclassifications, Available for Sale Investments		0
Amounts reclassified from accumulated other comprehensive loss, Available for Sale Investments	[2]	11
Net other comprehensive income (loss), Available for Sale Investments		11		(14)
Ending Balance, Available for Sale Investments		0		(11)
Beginning Balance, Pension Obligation		(7,414)		(5,069)
Amortization of the net actuarial loss and prior service credit, Pension Obligation		114		54
Other comprehensive loss before reclassifications, Pension Obligation		0
Amounts reclassified from accumulated other comprehensive loss, Pension Obligation		0
Net other comprehensive income (loss), Pension Obligation		114		54
Ending Balance, Pension Obligation		(7,300)		(5,015)
Beginning Balance, Accumulated Other Comprehensive Loss		(7,425)		(5,066)
Change In Unrealized Gain On Available For Sale Investments, Accumulated Other Comprehensive Loss				(14)
Amortization of net actuarial loss and prior service credit, Accumulated Other Comprehensive Loss		114		54
Other comprehensive loss before reclassifications, Accumulated Other Comprehensive Loss		(170)
Amounts reclassified from accumulated other comprehensive loss, Accumulated Other Comprehensive Loss		37
Net Other Comprehensive Income loss, Accumulated Other Comprehensive Loss		(19)		40
Ending Balance, Accumulated Other Comprehensive Loss		$ (7,444)		$ (5,026)

[1] Amount is included in interest expense in the consolidated statement of earnings.

[2] Amount was reclassified to retained earnings on December 29, 2017 in connection with the Company’s adoption of ASU No. 2016-01.