Segment Information Revenue and Long-Lived Assets (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Revenues $ 174,893 $ 195,616 $ 215,272 $ 175,673 $ 156,448 $ 164,454 $ 189,897 $ 168,585 $ 761,454 $ 679,384 $ 406,395
Long-Lived Assets 186,158       129,588       186,158 129,588  
United States
                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Revenues                 694,289 605,203 362,082
Long-Lived Assets 157,438       107,843       157,438 107,843  
Foreign
                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Revenues                 67,165 74,181 44,313
Long-Lived Assets $ 28,720       $ 21,745       $ 28,720 $ 21,745