Segment and Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Total revenues	$ 176,038	$ 144,744	$ 337,291	$ 278,868
United States	320,137		320,137		$ 317,206
Total long-lived assets	320,137		320,137		317,206
UNITED STATES
Total revenues	121,017	96,847	230,049	188,274
United States	218,818		218,818		216,099
Total long-lived assets	218,818		218,818		216,099
CANADA
Total revenues	18,947	17,436	37,086	34,944
IRELAND
Total revenues	10,820	11,414	20,755	22,509
All Other Countries [Member]
Total revenues	25,254	$ 19,047	49,401	$ 33,141
United States	101,319		101,319		101,107
Total long-lived assets	$ 101,319		$ 101,319		$ 101,107