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Long-Term Debt - Additional Information (Details)
$ in Thousands
4 Months Ended 12 Months Ended
Apr. 30, 2015
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Debt Instrument [Line Items]        
Interest expense   $ 17,856 $ 16,480 $ 14,982
Weighted average interest rate   3.65% 2.81%  
2013 Credit Facility        
Debt Instrument [Line Items]        
Line of credit facility amount drawn down   $ 115,000    
2013 Credit Facility Tranche B   $ 35,000    
2007 Credit Facility        
Debt Instrument [Line Items]        
Line of credit facility, maximum borrowing capacity $ 370,000      
Prepayments of four scheduled amortization payments $ 64,875      
Debt variable rate basis   LIBOR    
Number of amortization payments 5      
Frequency of Payments   quarterly    
Deferral of scheduled amortization payments November 2017      
2007 Credit Facility | Extension of the final maturity date        
Debt Instrument [Line Items]        
Maturity date   Dec. 31, 2019    
2007 Credit Facility | Prior to amendment        
Debt Instrument [Line Items]        
Credit facility margin   2.00%    
2007 Credit Facility | After the amendment        
Debt Instrument [Line Items]        
Credit facility margin   3.00%    
2008 Credit Facility        
Debt Instrument [Line Items]        
Line of credit facility, maximum borrowing capacity       350,000
Prepayments of four scheduled amortization payments $ 46,024      
Number of amortization payments 5      
Frequency of Payments   quarterly    
Deferral of scheduled amortization payments November 2017      
2008 Credit Facility | Extension of the final maturity date        
Debt Instrument [Line Items]        
Maturity date   Dec. 31, 2019    
2011 Credit Facility        
Debt Instrument [Line Items]        
Line of credit facility, maximum borrowing capacity $ 25,000     $ 25,000
Prepayments of four scheduled amortization payments $ 5,000      
Number of amortization payments 5      
Frequency of Payments   quarterly    
Deferral of scheduled amortization payments December 2017