CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss) including non-controlling interests	$ (60,481)	$ 44,832	$ 78,713	$ 178,545
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on derivatives designated and qualifying as cash flow hedges, net of tax of $116 and $334 in the three and nine months ended September 30, 2015; $(159) and $25 in the three and nine months ended September 30, 2014	(210)	313	311	(284)
Defined benefit pension plan activity, net of tax of $50,079 and $54,449 in the three and nine months ended September 30, 2015; $1,974 and $5,235 in the three and nine months ended September 30, 2014	80,766	2,909	87,875	7,989
Currency translation adjustment	(47,225)	(49,550)	(88,627)	(49,778)
Other comprehensive income (loss):	33,331	(46,328)	(441)	(42,073)
Comprehensive income (loss)	(27,150)	(1,496)	78,272	136,472
Comprehensive loss attributable to non-controlling interests	(91)	(797)	(663)	(164)
Comprehensive income (loss) attributable to shareholders	$ (27,059)	$ (699)	$ 78,935	$ 136,636