Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 183,766		$ 182,801		$ 165,903
Other comprehensive (loss) income, net of tax
Foreign currency translation adjustments	(27,461)		503		4,318
Interest rate hedge - net change in deferred gain (loss)	2,163		2,107		(76)
Pension - net change in deferred actuarial (loss) gain	(4,217)		(233)		(4,067)
Other comprehensive (loss) income, net of tax	(29,515)	[1]	2,377	[1]	175
Comprehensive income	$ 154,251		$ 185,178		$ 166,078

[1] Amounts in parentheses represent debits (deferred losses).