Segment Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues	$ 599,030	$ 520,801	$ 371,396
United States	317,206	221,922
Total long-lived assets	317,206	221,922
UNITED STATES
Revenues	403,279	369,507	233,585
United States	216,099	170,247
Total long-lived assets	216,099	170,247
CANADA
Revenues	70,434	73,130	79,656
IRELAND
Revenues	42,979	41,398	41,248
All Other Countries [Member]
Revenues	82,338	36,766	16,907
United States	101,107	51,675
Total long-lived assets	$ 101,107	$ 51,675