Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (10,222)	$ 3,778	$ 60,491
Other comprehensive income before reclassifications	76,995	(40,671)	(82,116)
Tax effect	(16,633)	15,984	17,543
Other comprehensive income before reclassifications, net of tax	60,362	(24,687)	(64,573)
Amounts reclassified out of AOCI	17,093	16,059	12,175
Tax effect	(5,599)	(5,372)	(4,315)
Amounts reclassified out of AOCI, net of tax	11,494	10,687	7,860
Other comprehensive income (loss)	71,856	(14,000)	(56,713)
Ending Balance	61,634	(10,222)	3,778
Pension and Other Post-Retirement Actuarial Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(178,956)	(149,197)	(119,990)
Other comprehensive income before reclassifications	52,545	(57,072)	(54,053)
Tax effect	(16,334)	16,626	16,975
Other comprehensive income before reclassifications, net of tax	36,211	(40,446)	(37,078)
Amounts reclassified out of AOCI	19,112	16,059	12,192
Tax effect	(6,285)	(5,372)	(4,321)
Amounts reclassified out of AOCI, net of tax	12,827	10,687	7,871
Other comprehensive income (loss)	49,038	(29,759)	(29,207)
Ending Balance	(129,918)	(178,956)	(149,197)
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	167,461	152,894	179,335
Other comprehensive income before reclassifications	23,537	14,567	(26,441)
Tax effect	0	0	0
Other comprehensive income before reclassifications, net of tax	23,537	14,567	(26,441)
Amounts reclassified out of AOCI	0	0	0
Tax effect	0	0	0
Amounts reclassified out of AOCI, net of tax	0	0	0
Other comprehensive income (loss)	23,537	14,567	(26,441)
Ending Balance	190,998	167,461	152,894
Unrealized Gain (Loss) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	1,273	81	1,146
Other comprehensive income before reclassifications	913	1,834	(1,622)
Tax effect	(299)	(642)	568
Other comprehensive income before reclassifications, net of tax	614	1,192	(1,054)
Amounts reclassified out of AOCI	(2,019)	0	(17)
Tax effect	686	0	6
Amounts reclassified out of AOCI, net of tax	(1,333)	0	(11)
Other comprehensive income (loss)	(719)	1,192	(1,065)
Ending Balance	$ 554	$ 1,273	$ 81