Other Liabilities (Details) - USD ($) $ in Thousands	Jul. 04, 2015	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Deferred compensation	$ 5,244	$ 4,919
Long-term income taxes payable	2,526	2,526
Asset retirement obligation	2,465	2,397
Post-retirement medical obligation	2,298	2,255
Long-term capital lease	926	1,406
Deferred service income-long term	329	1,051
Deferred income tax liabilities - long term	224	224
Other	407	474
Balance, end of the period	$ 14,419	$ 15,252	[1]

[1] The balance sheet as of December 31, 2014 has been derived from the audited financial statements at that date.