Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Total revenues	$ 144,744	$ 141,361	$ 278,868	$ 254,978
United States	262,683		262,683		221,922
Total long-lived assets	262,683		262,683		221,922
UNITED STATES
Total revenues	96,847	103,619	188,274	179,997
United States	166,668		166,668		170,247
Total long-lived assets	166,668		166,668		170,247
CANADA
Total revenues	17,436	18,587	34,944	37,145
IRELAND
Total revenues	11,414	10,307	22,509	20,405
All Other Countries [Member]
Total revenues	19,047	8,848	33,141	17,431
United States	96,015		96,015		51,675
Total long-lived assets	$ 96,015		$ 96,015		$ 51,675