CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income including non-controlling interests	$ 53,624	$ 68,318
Other comprehensive income, net of tax:
Unrealized gain (loss) on derivatives designated and qualifying as cash flow hedges, net of tax of $(203) and $58 in the three months ended March 31, 2016 and 2015	836	1,100
Defined benefit pension plan activity, net of tax of $911 and $2,395 in the three months ended March 31, 2016 and 2015	1,618	3,538
Currency translation adjustment	24,249	(56,552)
Other comprehensive income (loss)	26,703	(51,914)
Comprehensive income	80,327	16,404
Comprehensive income (loss) attributable to non-controlling interests	1	(577)
Comprehensive income attributable to shareholders	$ 80,326	$ 16,981