Segment and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Total revenues	$ 161,253	$ 134,124
United States	333,102		317,206
Total long-lived assets	333,102		317,206
UNITED STATES
Total revenues	109,032	91,428
United States	227,561		216,099
Total long-lived assets	227,561		216,099
CANADA
Total revenues	18,139	17,508
IRELAND
Total revenues	9,935	10,511
All Other Countries [Member]
Total revenues	24,147	14,677
United States	105,541		101,107
Total long-lived assets	$ 105,541		$ 101,107