Restatement - Consolidated Statements of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
Mar. 29, 2014	Mar. 30, 2013	Jun. 28, 2014	Jun. 29, 2013	Sep. 27, 2014	Sep. 28, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows from Operating Activities
Net Income	$ 5,159us-gaap_NetIncomeLoss	$ 3,971us-gaap_NetIncomeLoss	$ 11,778us-gaap_NetIncomeLoss	$ 9,637us-gaap_NetIncomeLoss	$ 14,711us-gaap_NetIncomeLoss	$ 16,622us-gaap_NetIncomeLoss	$ 19,867us-gaap_NetIncomeLoss	$ 11,378us-gaap_NetIncomeLoss	$ 17,623us-gaap_NetIncomeLoss
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization	7,426us-gaap_DepreciationAndAmortization	7,033us-gaap_DepreciationAndAmortization	15,125us-gaap_DepreciationAndAmortization	14,173us-gaap_DepreciationAndAmortization	21,829us-gaap_DepreciationAndAmortization	21,375us-gaap_DepreciationAndAmortization	29,024us-gaap_DepreciationAndAmortization	30,926us-gaap_DepreciationAndAmortization	29,413us-gaap_DepreciationAndAmortization
Asset impairments							0	6,975	0
Stock-based compensation expense	364us-gaap_ShareBasedCompensation	693us-gaap_ShareBasedCompensation	1,288us-gaap_ShareBasedCompensation	805us-gaap_ShareBasedCompensation	2,520us-gaap_ShareBasedCompensation	1,711us-gaap_ShareBasedCompensation	3,725us-gaap_ShareBasedCompensation	2,438us-gaap_ShareBasedCompensation	1,959us-gaap_ShareBasedCompensation
Deferred income taxes	(604)	(1,883)	998	1,868	2,073	833	345	(1,551)	1,098
(Recovery of) provision for doubtful accounts	(62)	(157)	(235)	(34)	(214)	(141)	(237)	(77)	78
Other	(757)us-gaap_OtherNoncashIncomeExpense	(266)us-gaap_OtherNoncashIncomeExpense	31us-gaap_OtherNoncashIncomeExpense	(101)us-gaap_OtherNoncashIncomeExpense	(149)us-gaap_OtherNoncashIncomeExpense	169us-gaap_OtherNoncashIncomeExpense	(5,713)us-gaap_OtherNoncashIncomeExpense	5,337us-gaap_OtherNoncashIncomeExpense	181us-gaap_OtherNoncashIncomeExpense
Changes in Assets and Liabilities:
Accounts receivable	(8,599)	1,066	(13,066)	(8,243)	(12,273)	4,804	1,086	5,468	(1,204)
Inventories	(8,388)us-gaap_IncreaseDecreaseInInventories	(993)us-gaap_IncreaseDecreaseInInventories	(1,694)us-gaap_IncreaseDecreaseInInventories	(357)us-gaap_IncreaseDecreaseInInventories	(4,961)us-gaap_IncreaseDecreaseInInventories	(1,055)us-gaap_IncreaseDecreaseInInventories	(2,335)us-gaap_IncreaseDecreaseInInventories	6,962us-gaap_IncreaseDecreaseInInventories	5,870us-gaap_IncreaseDecreaseInInventories
Production cost of contracts	513	(2,559)	(1,734)	(1,843)	(1,408)	(3,396)	(3,513)	(5,101)	(1,324)
Other assets	5,440	1,456	6,563	(3,473)	6,633	(10,482)	4,800	(12,173)	6,829
Accounts payable	(4,138)	(2,097)	(4,363)	(1,714)	(2,447)	(2,910)	410	4,533	(8,097)
Accrued and other liabilities	(6,067)	(12,386)	835	(3,775)	(5,400)	(12,819)	6,103	(9,153)	(4,892)
Net Cash Provided by Operating Activities	(9,713)	(6,122)	15,526	6,943	20,914	14,711	53,422	45,962	47,534
Cash Flows from Investing Activities
Purchases of property and equipment	(2,192)	(2,612)	(5,997)	(5,253)	(9,329)	(7,321)	(18,096)	(12,403)	(15,813)
Proceeds from sales of assets	5	5	51	111	83	123	91	139	31
Insurance recoveries related to property and equipment			0		1,600		2,550	0	0
Net Cash Used in Investing Activities	(2,187)	(2,607)	(5,946)	(5,142)	(7,646)	(7,198)	(15,455)	(12,264)	(15,782)
Cash Flows from Financing Activities
Repayment of term loan and other debt	(7,506)us-gaap_RepaymentsOfDebt	(7,506)us-gaap_RepaymentsOfDebt	(15,012)us-gaap_RepaymentsOfDebt	(15,012)us-gaap_RepaymentsOfDebt	(22,519)us-gaap_RepaymentsOfDebt	(22,518)us-gaap_RepaymentsOfDebt	(42,650)us-gaap_RepaymentsOfDebt	(33,024)us-gaap_RepaymentsOfDebt	(26,478)us-gaap_RepaymentsOfDebt
Debt issue cost paid		(181)us-gaap_PaymentsOfDebtIssuanceCosts		(181)us-gaap_PaymentsOfDebtIssuanceCosts		(181)us-gaap_PaymentsOfDebtIssuanceCosts	0us-gaap_PaymentsOfDebtIssuanceCosts	(365)us-gaap_PaymentsOfDebtIssuanceCosts	0us-gaap_PaymentsOfDebtIssuanceCosts
Net proceeds from issuance of common stock under stock plans	7	(127)	369	365	1,289	1,246	1,356	1,968	(186)
Net Cash Used in Financing Activities	(7,499)	(7,814)	(14,643)	(14,828)	(21,230)	(21,453)	(41,154)	(31,421)	(26,664)
Net (Decrease) Increase in Cash and Cash Equivalents	(19,399)	(16,543)	(5,063)	(13,027)	(7,962)	(13,940)	(3,187)	2,277	5,088
Cash and Cash Equivalents at Beginning of Year	48,814	46,537	48,814	46,537	48,814	46,537	48,814	46,537	41,449
Cash and Cash Equivalents at End of Year	29,415	29,994	43,751	33,510	40,852	32,597	45,627	48,814	46,537
Supplemental Disclosures of Cash Flow Information
Interest paid	11,397us-gaap_InterestPaid	12,037us-gaap_InterestPaid	1,440us-gaap_InterestPaid	1,951us-gaap_InterestPaid	24,090us-gaap_InterestPaid	25,640us-gaap_InterestPaid	25,105us-gaap_InterestPaid	27,614us-gaap_InterestPaid	31,505us-gaap_InterestPaid
Taxes paid	58us-gaap_IncomeTaxesPaid	563us-gaap_IncomeTaxesPaid	3,249us-gaap_IncomeTaxesPaid	1,743us-gaap_IncomeTaxesPaid	3,410us-gaap_IncomeTaxesPaid	6,542us-gaap_IncomeTaxesPaid	3,476us-gaap_IncomeTaxesPaid	7,835us-gaap_IncomeTaxesPaid	1,953us-gaap_IncomeTaxesPaid
Non-cash activities:
Purchases of property and equipment not paid	182		722		418		1,458	1,000	0
As Reported
Cash Flows from Operating Activities
Net Income	4,629	3,707	11,101	9,211	13,723	13,847		9,343	16,437
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization	7,426	7,033	15,125	14,173	21,829	21,375		30,926	29,413
Asset impairments								6,975
Stock-based compensation expense	364	693	1,288	805	2,520	1,711		2,438	1,959
Deferred income taxes	(919)	(2,040)	595	1,615	1,775	45		(2,242)	(142)
(Recovery of) provision for doubtful accounts	(62)	(157)	(235)	(34)	(214)	(141)		(77)	78
Other	88	246	1,111	809	649	1,434		6,223	2,391
Changes in Assets and Liabilities:
Accounts receivable	(8,599)	1,066	(13,066)	(8,243)	(12,273)	4,804		5,468	(1,204)
Inventories	(8,388)	(1,084)	(1,694)	(588)	(4,961)	(206)		7,811	6,185
Production cost of contracts	513	(2,559)	(1,734)	(1,843)	(1,408)	(3,396)		(5,101)	(1,324)
Other assets	5,440	1,456	6,563	(3,473)	7,121	(9,033)		(11,192)	6,846
Accounts payable	(4,138)	(2,097)	(4,363)	(1,714)	(2,447)	(2,910)		4,533	(8,097)
Accrued and other liabilities	(6,067)	(12,386)	835	(3,775)	(5,400)	(12,819)		(9,143)	(5,008)
Net Cash Provided by Operating Activities	(9,713)	(6,122)	15,526	6,943	20,914	14,711		45,962	47,534
Cash Flows from Investing Activities
Purchases of property and equipment	(2,192)	(2,612)	(5,997)	(5,253)	(9,329)	(7,321)		(12,403)	(15,813)
Proceeds from sales of assets	5	5	51	111	83	123		139	31
Insurance recoveries related to property and equipment			0		1,600
Net Cash Used in Investing Activities	(2,187)	(2,607)	(5,946)	(5,142)	(7,646)	(7,198)		(12,264)	(15,782)
Cash Flows from Financing Activities
Repayment of term loan and other debt	(7,506)	(7,506)	(15,012)	(15,012)	(22,519)	(22,518)		(33,024)	(26,478)
Debt issue cost paid		(181)		(181)		(181)		(365)
Net proceeds from issuance of common stock under stock plans	7	(127)	369	365	1,289	1,246		1,968	(186)
Net Cash Used in Financing Activities	(7,499)	(7,814)	(14,643)	(14,828)	(21,230)	(21,453)		(31,421)	(26,664)
Net (Decrease) Increase in Cash and Cash Equivalents	(19,399)	(16,543)	(5,063)	(13,027)	(7,962)	(13,940)		2,277	5,088
Cash and Cash Equivalents at Beginning of Year	48,814	46,537	48,814	46,537	48,814	46,537	48,814	46,537	41,449
Cash and Cash Equivalents at End of Year	29,415	29,994	43,751	33,510	40,852	32,597		48,814	46,537
Supplemental Disclosures of Cash Flow Information
Interest paid	11,397	12,037	1,440	1,951	24,090	25,640		27,614	31,505
Taxes paid	58	563	3,249	1,743	3,410	6,542		7,835	1,953
Non-cash activities:
Purchases of property and equipment not paid	182		722		418			1,000
Restatement Adjustment
Cash Flows from Operating Activities
Net Income	530	264	677	426	988	2,775		2,035	1,186
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization	0	0	0	0	0	0		0	0
Asset impairments								0
Stock-based compensation expense	0	0	0	0	0	0		0	0
Deferred income taxes	315	157	403	253	298	788		691	1,240
(Recovery of) provision for doubtful accounts	0	0	0	0	0	0		0	0
Other	(845)	(512)	(1,080)	(910)	(798)	(1,265)		(886)	(2,210)
Changes in Assets and Liabilities:
Accounts receivable	0	0	0	0	0	0		0	0
Inventories	0	91	0	231	0	(849)		(849)	(315)
Production cost of contracts	0	0	0	0	0	0		0	0
Other assets	0	0	0	0	(488)	(1,449)		(981)	(17)
Accounts payable	0	0	0	0	0	0		0	0
Accrued and other liabilities	0	0	0	0	0	0		(10)	116
Net Cash Provided by Operating Activities	0	0	0	0	0	0		0	0
Cash Flows from Investing Activities
Purchases of property and equipment	0	0	0	0	0	0		0	0
Proceeds from sales of assets	0	0	0	0	0	0		0	0
Insurance recoveries related to property and equipment			0		0
Net Cash Used in Investing Activities	0	0	0	0	0	0		0	0
Cash Flows from Financing Activities
Repayment of term loan and other debt	0	0	0	0	0	0		0	0
Debt issue cost paid		0		0		0		0
Net proceeds from issuance of common stock under stock plans	0	0	0	0	0	0		0	0
Net Cash Used in Financing Activities	0	0	0	0	0	0		0	0
Net (Decrease) Increase in Cash and Cash Equivalents	0	0	0	0	0	0		0	0
Cash and Cash Equivalents at Beginning of Year	0	0	0	0	0	0	0	0	0
Cash and Cash Equivalents at End of Year	0	0	0	0	0	0		0	0
Supplemental Disclosures of Cash Flow Information
Interest paid	0	0	0	0	0	0		0	0
Taxes paid	0	0	0	0	0	0		0	0
Non-cash activities:
Purchases of property and equipment not paid	$ 0		$ 0		$ 0			$ 0

Increase decrease in carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer.) These costs cover all other liabilities not included in accrued liabilities.

No definition available.