Annual report pursuant to Section 13 and 15(d)

Borrowings (Term Loans) (Narrative) (Details)

v3.8.0.1
Borrowings (Term Loans) (Narrative) (Details) - USD ($)
12 Months Ended
May 19, 2017
Oct. 11, 2016
Oct. 03, 2016
Oct. 08, 2014
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Sep. 30, 2017
Mar. 11, 2014
Line of Credit Facility [Line Items]                  
Gain (loss) on early extinguishment of debt         $ 0 $ (12,883,000) $ 0    
Unamortized deferred financing costs         $ 12,398,000 $ 9,781,000      
Secured Second Lien Term Loan                  
Line of Credit Facility [Line Items]                  
Debt, initial commitment                 $ 100,000,000
Debt, additional availability                 25,000,000
Debt instrument maturity date         Sep. 11, 2019        
Gain (loss) on early extinguishment of debt       $ (3,054,000)          
Secured Second Lien Term Loan | Prior to March 11, 2015                  
Line of Credit Facility [Line Items]                  
Debt instrument redemption price percent (as a percent)         102.00%        
Secured Second Lien Term Loan | On or After March 15, 2015 But Before March 15, 2016                  
Line of Credit Facility [Line Items]                  
Debt instrument redemption price percent (as a percent)         101.00%        
Secured Second Lien Term Loan | On or After March 15, 2016                  
Line of Credit Facility [Line Items]                  
Debt instrument redemption price percent (as a percent)         100.00%        
Secured Second Lien Term Loan | Prior to October 8, 2016                  
Line of Credit Facility [Line Items]                  
Debt instrument redemption price percent (as a percent)       102.00%          
Secured Second Lien Term Loan | On or After October 8, 2016 But Before October 8, 2017                  
Line of Credit Facility [Line Items]                  
Debt instrument redemption price percent (as a percent)       101.00%          
Secured Second Lien Term Loan | On or After October 8, 2017                  
Line of Credit Facility [Line Items]                  
Debt instrument redemption price percent (as a percent)       100.00%          
Secured Second Lien Term Loan | Maximum                  
Line of Credit Facility [Line Items]                  
Debt instrument aggregate principal amount                 $ 125,000,000
New Secured Second Lien Term Loan Facility                  
Line of Credit Facility [Line Items]                  
Debt instrument maturity date         Oct. 08, 2021        
Gain (loss) on early extinguishment of debt   $ 12,883,000              
Debt instrument interest rate       7.50%          
Debt instrument, prepayment fees   3,000,000              
Unamortized deferred financing costs   $ 9,883,000              
New Secured Second Lien Term Loan Facility | Interest Rate Floor                  
Line of Credit Facility [Line Items]                  
Debt instrument interest rate       1.00%          
6.125% senior unsecured notes due 2024                  
Line of Credit Facility [Line Items]                  
Debt instrument aggregate principal amount $ 200,000,000   $ 400,000,000            
Debt instrument maturity date     Oct. 01, 2024            
Debt instrument redemption price percent (as a percent) 104.125%                
Debt instrument, interest rate, stated (as a percent) 6.125%   6.125%   6.125%     6.125%