Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net Income (Loss) Attributable to Parent	$ (105,900)	$ 47,600	$ 41,900	$ 19,100	$ 60,000	$ (15,800)	$ 54,400	$ 33,900	$ 2,652	$ 132,455	$ 258,411
Income Tax Expense (Benefit)									(258,679)	(77,380)	(148,351)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance -				(621,377)				(535,534)	(621,377)	(535,534)
Other comprehensive income (loss) before reclassifications									110,990	(94,869)
Amounts reclassified from AOCL									8,763	9,026
Other comprehensive income (loss)									119,753	(85,843)	(156,696)
Balance -	(501,624)				(621,377)				(501,624)	(621,377)	(535,534)
Accumulated Other Comprehensive Income (Loss), accumulated Net Gain (Loss) from Net investment hedge, Net of Tax									22,500	1,400
Net of tax									(8,763)	(9,026)
Foreign Currency Translation Items
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance -				(483,609)				(411,615)	(483,609)	(411,615)
Other comprehensive income (loss) before reclassifications									98,308	(71,994)
Amounts reclassified from AOCL									522	0
Other comprehensive income (loss)									98,830	(71,994)
Balance -	(384,779)				(483,609)				(384,779)	(483,609)	(411,615)
Net of tax									(522)	0
Pension and other post-retirement effects
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance -				(136,530)				(120,461)	(136,530)	(120,461)
Other comprehensive income (loss) before reclassifications									12,557	(23,939)
Amounts reclassified from AOCL									8,218	7,870
Other comprehensive income (loss)									20,775	(16,069)
Balance -	(115,755)				(136,530)				(115,755)	(136,530)	(120,461)
Tax benefit									3,764	3,243
Amount of settlement of reclassification adjustment from accumulated other comprehensive income (loss)									(2,113)	(871)
Net of tax									(8,218)	(7,870)
Cash flow hedging activity
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance -				$ (1,238)				$ (3,458)	(1,238)	(3,458)
Other comprehensive income (loss) before reclassifications									125	1,064
Amounts reclassified from AOCL									23	1,156
Other comprehensive income (loss)									148	2,220
Balance -	(1,090)				(1,238)				(1,090)	(1,238)	(3,458)
Tax benefit									7	375
Net of tax									(23)	(1,156)
Noncontrolling Interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive income (loss)									438	713	1,437
Foreign currency translation adjustments, attributable to noncontrolling interest	$ 3,800				$ 3,400				3,800	3,400	$ 2,700
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification from AOCI, before tax									(9,761)	(9,750)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification from AOCI, before tax									(108)	(492)
Sales | Cash flow hedging activity
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification from AOCI, before tax									(30)	(1,531)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign Currency Translation Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net Income (Loss) Attributable to Parent									0	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign Currency Translation Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax									$ (522)	$ 0