Goodwill and Intangible Assets, Net (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Changes in gross carrying amount of finite-lived intangible assets
Gross Carrying Amount	$ 63,413	$ 39,366	$ 63,413	$ 39,366	$ 46,026
Accumulated Amortization	(21,884)	(17,315)	(21,884)	(17,315)	(18,170)
Net Carrying Amount	41,529	22,051	41,529	22,051	27,856
Amortization expense of intangible assets	1,900	1,100	3,714	2,200
Estimated future amortization of intangible assets
Final six months of 2012			3,358
2013			6,590
2014			6,380
2015			5,621
2016			5,568
2017			3,800
Thereafter			10,212
Total			41,529
North America
Changes in gross carrying amount of finite-lived intangible assets
Gross Carrying Amount	35,581	24,022	35,581	24,022	32,912
Accumulated Amortization	(15,350)	(12,094)	(15,350)	(12,094)	(13,288)
Net Carrying Amount	20,231	11,928	20,231	11,928	19,624
Europe
Changes in gross carrying amount of finite-lived intangible assets
Gross Carrying Amount	27,832	15,344	27,832	15,344	13,114
Accumulated Amortization	(6,534)	(5,221)	(6,534)	(5,221)	(4,882)
Net Carrying Amount	$ 21,298	$ 10,123	$ 21,298	$ 10,123	$ 8,232