Accumulated Other Comprehensive Loss (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Line items affected on the condensed consolidated statements of operations for components reclassified from accumulated other comprehensive income (loss)
Amortization of unrecognized employee benefit costs	$ 2,232	$ 1,971
Amortization of unrecognized employee benefit costs, Income tax provision	(806)	(705)
Amortization of unrecognized employee benefit costs	1,426	1,266
Realized gains/losses from sale of marketable securities, Income tax provision	2	11
Realized gains on sale of marketable securities Net of tax	(5)	(21)
Realized losses (gains) from settlement of cash flow hedges:
Foreign currency sales contracts	7	198
Foreign currency sales and purchase contracts, futures contracts - copper and aluminum, Income tax (provision) benefit	(4)	(75)
Realized losses from settlement of cash flow hedges	3	123
Foreign currency purchases contracts [Member]
Realized losses (gains) from settlement of cash flow hedges:
Realized losses from settlement of cash flow hedges	5	4
Futures contracts - copper and aluminum [Member]
Realized losses (gains) from settlement of cash flow hedges:
Realized losses from settlement of cash flow hedges	(8)	(177)
Costs of products sold (excluding depreciation) [Member]
Line items affected on the condensed consolidated statements of operations for components reclassified from accumulated other comprehensive income (loss)
Amortization of unrecognized employee benefit costs	1,440	1,296
Costs of products sold (excluding depreciation) [Member] | Futures contracts - copper and aluminum [Member]
Realized losses (gains) from settlement of cash flow hedges:
Foreign currency sales contracts	14	284
Depreciation [Member] | Foreign currency purchases contracts [Member]
Realized losses (gains) from settlement of cash flow hedges:
Foreign currency sales contracts	(7)	(7)
Selling and administrative [Member]
Line items affected on the condensed consolidated statements of operations for components reclassified from accumulated other comprehensive income (loss)
Amortization of unrecognized employee benefit costs	573	480
Realized (gains) on sale of marketable securities, Selling and administrative	(7)	(32)
Other income (expense) [Member]
Line items affected on the condensed consolidated statements of operations for components reclassified from accumulated other comprehensive income (loss)
Amortization of unrecognized employee benefit costs	219	195
Net Sales [Member] | Foreign currency sales contracts [Member]
Realized losses (gains) from settlement of cash flow hedges:
Foreign currency sales contracts	$ 0	$ (79)