Lease Exit Costs (Details) (USD $)
1 Months Ended
Sep. 30, 2014
Aug. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Bannockburn        
Operating Leased Assets [Line Items]        
Lease loss accrual, cash outflow     $ 7,000,000  
Bannockburn | Accrued expenses and other current liabilities        
Operating Leased Assets [Line Items]        
Lease loss accrual     6,900,000  
Bannockburn | Selling, general and administrative expenses        
Operating Leased Assets [Line Items]        
Lease loss expense 5,700,000      
Maryland        
Operating Leased Assets [Line Items]        
Lease loss accrual, cash outflow     6,100,000  
Maryland | Accrued expenses and other current liabilities        
Operating Leased Assets [Line Items]        
Lease loss accrual     5,215,000 5,774,000
Maryland | Selling, general and administrative expenses        
Operating Leased Assets [Line Items]        
Lease loss expense   $ 5,600,000