Equity and Noncontrolling Interest - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Balance at Beginning of Period	$ (74,351)	$ (72,938)	$ (65,100)	$ (87,407)
Other Comprehensive Income (Loss) Before Reclassifications	(6,448)	5,994	(17,498)	19,004
Amounts Reclassified from AOCI	687	530	2,758	3,395
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(5,761)	6,524	(14,740)	22,399
Related Tax Amounts	(220)	(259)	(492)	(1,665)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(5,981)	6,265	(15,232)	20,734
Accumulated Other Comprehensive Income (Loss), Balance at End of Period	(80,332)	(66,673)	(80,332)	(66,673)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Balance at Beginning of Period	(42,069)	(40,062)	(31,893)	(52,255)
Other Comprehensive Income (Loss) Before Reclassifications	(6,821)	5,917	(16,997)	18,110
Amounts Reclassified from AOCI	0	0	0	0
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(6,821)	5,917	(16,997)	18,110
Related Tax Amounts	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(6,821)	5,917	(16,997)	18,110
Accumulated Other Comprehensive Income (Loss), Balance at End of Period	(48,890)	(34,145)	(48,890)	(34,145)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Balance at Beginning of Period	(32,513)	(34,059)	(34,093)	(36,168)
Other Comprehensive Income (Loss) Before Reclassifications	99	(611)	563	(684)
Amounts Reclassified from AOCI	756	784	2,318	4,284
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	855	173	2,881	3,600
Related Tax Amounts	(177)	(111)	(623)	(1,429)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	678	62	2,258	2,171
Accumulated Other Comprehensive Income (Loss), Balance at End of Period	(31,835)	(33,997)	(31,835)	(33,997)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Balance at Beginning of Period	231	1,183	886	1,016
Other Comprehensive Income (Loss) Before Reclassifications	274	688	(1,064)	1,578
Amounts Reclassified from AOCI	(69)	(254)	440	(889)
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	205	434	(624)	689
Related Tax Amounts	(43)	(148)	131	(236)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	162	286	(493)	453
Accumulated Other Comprehensive Income (Loss), Balance at End of Period	$ 393	$ 1,469	$ 393	$ 1,469