Segment Information - Financial Information by Major Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues:
Total revenues	$ 972,792	$ 1,025,231	$ 942,364
Long-lived assets:
Total long-lived assets	225,356	229,714	204,864
United States
Revenues:
Total revenues	656,927	700,414	660,998
Long-lived assets:
Total long-lived assets	132,315	141,727	145,217
Canada
Revenues:
Total revenues	148,934	151,070	140,374
Long-lived assets:
Total long-lived assets	82,986	76,067	47,624
United Kingdom
Revenues:
Total revenues	151,217	153,027	124,208
Long-lived assets:
Total long-lived assets	9,631	9,757	8,165
Other International
Revenues:
Total revenues	15,714	20,720	16,784
Long-lived assets:
Total long-lived assets	$ 424	$ 2,163	$ 3,858