CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income including non-controlling interests	$ 127,412	$ 253,880	$ 291,687
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges, net of tax of $336 in 2015; $(121) in 2014; $(141) in 2013	557	(378)	289
Defined pension plan activity, net of tax of $61,538 in 2015, $(20,951) in 2014; $60,556 in 2013	98,117	(37,200)	101,151
Currency translation adjustment	(106,935)	(98,365)	(19,955)
Transactions with non-controlling interests	(7)	(4)	155
Other comprehensive income (loss)	(8,268)	(135,947)	81,640
Comprehensive income	119,144	117,933	373,327
Comprehensive (loss) income attributable to non-controlling interests	(689)	(72)	(3,912)
Comprehensive income attributable to shareholders	119,833	118,005	377,239
Accumulated Other Comprehensive Income (Loss) [Member]
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges, net of tax of $336 in 2015; $(121) in 2014; $(141) in 2013	557	(378)	289
Defined pension plan activity, net of tax of $61,538 in 2015, $(20,951) in 2014; $60,556 in 2013	98,117	(37,200)	101,151
Currency translation adjustment	$ (106,312)	$ (99,099)	$ (18,136)