Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (69,140)	$ 61,634	$ (10,222)
Other comprehensive income before reclassifications	(66,440)	(164,722)	76,995
Tax effect	(3,670)	17,359	(16,633)
Other comprehensive income before reclassifications, net of tax	(70,110)	(147,363)	60,362
Amounts reclassified out of AOCI	12,189	25,526	17,093
Tax effect	(4,266)	(8,937)	(5,599)
Amounts reclassified out of AOCI, net of tax	7,923	16,589	11,494
Other comprehensive income (loss)	(62,187)	(130,774)	71,856
Ending Balance	(131,327)	(69,140)	61,634
Pension and Other Post-Retirement Actuarial Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(155,760)	(129,918)	(178,956)
Other comprehensive income before reclassifications	15,169	(60,602)	52,545
Tax effect	(4,196)	18,117	(16,334)
Other comprehensive income before reclassifications, net of tax	10,973	(42,485)	36,211
Amounts reclassified out of AOCI	12,869	25,604	19,112
Tax effect	(4,504)	(8,961)	(6,285)
Amounts reclassified out of AOCI, net of tax	8,365	16,643	12,827
Other comprehensive income (loss)	19,338	(25,842)	49,038
Ending Balance	(136,422)	(155,760)	(129,918)
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	84,703	190,998	167,461
Other comprehensive income before reclassifications	(80,106)	(106,295)	23,537
Tax effect	0	0	0
Other comprehensive income before reclassifications, net of tax	(80,106)	(106,295)	23,537
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)	(80,106)	(106,295)	23,537
Ending Balance	4,597	84,703	190,998
Unrealized Gain (Loss) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	1,917	554	1,273
Other comprehensive income before reclassifications	(1,503)	2,175	913
Tax effect	526	(758)	(299)
Other comprehensive income before reclassifications, net of tax	(977)	1,417	614
Amounts reclassified out of AOCI	(680)	(78)	(2,019)
Tax effect	238	24	686
Amounts reclassified out of AOCI, net of tax	(442)	(54)	(1,333)
Other comprehensive income (loss)	(1,419)	1,363	(719)
Ending Balance	$ 498	$ 1,917	$ 554