Restatement - Consolidated Statements of Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 31, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Jun. 28, 2014	Jun. 29, 2013	Sep. 27, 2014	Sep. 28, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net Income	$ 5,156	$ 2,933	$ 6,619	$ 5,159	$ (5,244)	$ 6,985	$ 5,666	$ 3,971	$ 11,778	$ 9,637	$ 14,711	$ 16,622	$ 19,867	$ 11,378	$ 17,623
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Amortization of actuarial loss included in net income, net of tax benefit of $156, $408 and $427 for 2014, 2013 and 2012, respectively		(66)	(57)	(69)		(172)	(172)	(172)	(126)	(344)	(192)	(516)	263	685	720
Actuarial gain (loss) arising during the period, net of tax expense (benefit)													(3,052)	2,921	(863)
Other Comprehensive (Loss) Income		(66)	(57)	(69)		(172)	(172)	(172)	(126)	(344)	(192)	(516)	(2,789)	3,606	(143)
Comprehensive Income		2,867	6,562	5,090		6,813	5,494	3,799	11,652	9,293	14,519	16,106	17,078	14,984	17,480
As Reported
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net Income		2,622	6,472	4,629		4,636	5,504	3,707	11,101	9,211	13,723	13,847		9,343	16,437
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Amortization of actuarial loss included in net income, net of tax benefit of $156, $408 and $427 for 2014, 2013 and 2012, respectively		(66)	(57)	(69)		(172)	(172)	(172)	(126)	(344)	(192)	(516)		685	720
Actuarial gain (loss) arising during the period, net of tax expense (benefit)														2,921	(863)
Other Comprehensive (Loss) Income		(66)	(57)	(69)		(172)	(172)	(172)	(126)	(344)	(192)	(516)		3,606	(143)
Comprehensive Income		2,556	6,415	4,560		4,464	5,332	3,535	10,975	8,867	13,531	13,331		12,949	16,294
Restatement Adjustment
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net Income		311	147	530		2,349	162	264	677	426	988	2,775		2,035	1,186
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Amortization of actuarial loss included in net income, net of tax benefit of $156, $408 and $427 for 2014, 2013 and 2012, respectively		0	0	0		0	0	0	0	0	0	0		0	0
Actuarial gain (loss) arising during the period, net of tax expense (benefit)														0	0
Other Comprehensive (Loss) Income		0	0	0		0	0	0	0	0	0	0		0	0
Comprehensive Income		$ 311	$ 147	$ 530		$ 2,349	$ 162	$ 264	$ 677	$ 426	$ 988	$ 2,775		$ 2,035	$ 1,186