Basis of Presentation and Summary of Significant Accounting Policies - Pro Forma Information (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended
Jun. 30, 2011
Jun. 30, 2011
Sep. 30, 2012
acquisition
Dec. 31, 2011
acquisition
Accounting Policies [Abstract]        
Number of businesses acquired     0 4
Revenue $ 82,198 $ 244,710    
Net loss $ (4,484) $ (14,185)