Fair Value (Details) (USD $)
 3 Months Ended
Mar. 31, 2013
Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Contingent consideration, change in value of contingent purchase price $ 300,000  
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Derivative   2,639,000
Interest Rate Cash Flow Hedge Liability at Fair Value 2,038,000  
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Contingent purchase price consideration 19,615,000 49,183,000
Payments made to reduce the fair value or contingent purchase price considerations 25,500,000  
Adjustments made to reduce the fair value of contingent purchase price considerations 4,500,000  
Fair Value, Measurements, Recurring | Estimate of Fair Value, Fair Value Disclosure
    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Contingent purchase price consideration 19,615,000 49,183,000
Derivative $ 2,038,000 $ 2,639,000