Accumulated Other Comprehensive Loss - Line Items Affected on Condensed Consolidated Statements of Operations for Components Reclassified from Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Costs of products sold (excluding depreciation)	$ 55,310	$ 54,302	$ 110,400	$ 110,538
Selling and administrative	9,298	9,973	19,156	20,400
Other income (expense)	403	226	1,007	463
Income tax provision	581	770	901	2,145
Net income	(1,106)	(1,508)	(1,232)	(3,508)
Net sales	(69,938)	(69,956)	(139,562)	(143,561)
Depreciation	2,914	2,754	5,885	5,579
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)	1,380	1,265	2,820	2,561
Selling and administrative	536	497	1,109	977
Other income (expense)	214	190	433	385
Total before income tax	2,130	1,952	4,362	3,923
Income tax provision	(769)	(701)	(1,575)	(1,406)
Net income	1,361	1,251	2,787	2,517
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized (Gains) on Sale of Marketable Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling and administrative	(46)	(10)	(53)	(42)
Income tax provision	17	4	19	15
Net income	(29)	(6)	(34)	(27)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Losses (Gains) from Settlement of Cash Flow Hedges: [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before income tax	94	(45)	101	153
Income tax provision	(35)	16	(39)	(59)
Net income	59	(29)	62	94
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Losses (Gains) from Settlement of Cash Flow Hedges: [Member] | Foreign Currency Sales Contracts - Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net sales	0	0	0	(79)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Losses (Gains) from Settlement of Cash Flow Hedges: [Member] | Foreign Currency Purchases Contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Depreciation	(7)	(7)	(14)	(14)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Realized Losses (Gains) 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)	$ 101	$ (38)	$ 115	$ 246