Net Revenues by Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Net revenues	$ 163,828	$ 145,626	$ 317,408	$ 280,705
United States
Segment Reporting Information [Line Items]
Net revenues	121,651	110,838	241,692	214,096
the Netherlands
Segment Reporting Information [Line Items]
Net revenues	32,363	28,715	63,458	55,080
Other international
Segment Reporting Information [Line Items]
Net revenues	$ 9,814	$ 6,073	$ 12,258	$ 11,529