Goodwill (Details 2) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Changes in the carrying amount of goodwill
Balance at January 1, 2014	$ 281,714
Effect of foreign exchange rate changes	(9,723)
Acquisition	1,282
Balance at September 30, 2014	273,273
International
Changes in the carrying amount of goodwill
Balance at January 1, 2014	148,033
Effect of foreign exchange rate changes	(9,723)
Acquisition	1,282
Balance at September 30, 2014	139,592
North America
Changes in the carrying amount of goodwill
Balance at January 1, 2014	133,681
Effect of foreign exchange rate changes	0
Acquisition	0
Balance at September 30, 2014	$ 133,681