Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 37,736	$ 36,675
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(278)	(3,789)
Interest rate hedge – gain	470	561
Pension – actuarial gain	15	23
Other comprehensive income (loss)	207	(3,205)
Comprehensive income	$ 37,943	$ 33,470