Accumulated Other Comprehensive Loss - Line Items Affected on Consolidated Statements of Operations for Components Reclassified from Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Costs of products sold (excluding depreciation)									$ 217,342	$ 225,906	$ 256,030
Selling and administrative									39,682	40,530	41,887
Other income (expense)									(1,631)	(942)	(1,578)
Income tax provision									(5,813)	(5,218)	(12,916)
Net income	(1,500)	12,705	1,106	126	3,319	1,528	1,508	2,000	12,437	8,355	21,309
Net sales	77,055	64,433	69,938	69,624	77,154	72,190	69,956	73,605	281,050	292,905	344,816
Depreciation									(11,342)	(10,661)	(10,153)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Amortization of Unrecognized Employee Benefit Costs [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Costs of products sold (excluding depreciation)									5,691	4,807	3,764
Selling and administrative									2,241	1,939	1,371
Other income (expense)									867	763	595
Total before income tax									8,799	7,509	5,730
Income tax provision									(3,156)	(3,547)	(2,066)
Net income									5,643	3,962	3,664
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Gains/Losses on Sale of Marketable Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling and administrative									(87)	(120)	20
Income tax provision									30	42	(7)
Net income									(57)	(78)	13
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Gains/Losses from Settlement of Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before income tax									392	174	(613)
Income tax provision									(146)	(67)	230
Net income									246	107	(383)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Gains/Losses from Settlement of Cash Flow Hedges [Member] | Foreign Currency Sales Contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net sales									0	(197)	(228)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Gains/Losses from Settlement of Cash Flow Hedges [Member] | Foreign Currency Purchase Contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Depreciation									(27)	(27)	(32)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Gains/Losses from Settlement of Cash Flow Hedges [Member] | Futures Contracts - Copper and Aluminum [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Costs of products sold (excluding depreciation)									$ 419	$ 398	$ (353)