CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income including non-controlling interests	$ 77,289	$ 72,527	$ 133,713	$ 139,370
Other comprehensive income (loss), net of tax:
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges, net of tax of $90 and $184 in the three and six months ended June 30, 2014; $(217) and $(331) in the three and six months ended June 30, 2013	(176)	(15)	(597)	587
Defined benefit pension plan activity, net of tax of $1,423 and $3,261 in the three and six months ended June 30, 2014; $3,114 and $6,182 in the three and six months ended June 30, 2013	2,536	4,972	5,080	10,077
Currency translation adjustment	12,130	(20,861)	(228)	(35,100)
Other comprehensive income (loss):	14,490	(15,904)	4,255	(24,436)
Comprehensive income	91,779	56,623	137,968	114,934
Comprehensive (loss) income attributable to non-controlling interests	(19)	(241)	633	(91)
Comprehensive income attributable to shareholders	$ 91,798	$ 56,864	$ 137,335	$ 115,025