v3.3.1.900
Long-Term Debt - Senior Notes Issuances (Details) - Senior Notes - USD ($)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Debt Instrument [Line Items]      
Debt Issuance Costs $ 376,000 $ 375,000 $ 223,000
2011 Senior Notes      
Debt Instrument [Line Items]      
Principal 107,500,000    
Debt Issuance Costs 2,811,000    
Net Proceeds $ 104,689,000    
Coupon rate 8.25%    
Effective interest rate 8.47%    
2012 Senior Notes      
Debt Instrument [Line Items]      
Principal $ 100,000,000    
Debt Issuance Costs 3,406,000    
Net Proceeds $ 96,594,000    
Coupon rate 8.00%    
Effective interest rate 8.28%    
2013 Senior Notes      
Debt Instrument [Line Items]      
Principal $ 152,500,000    
Debt Issuance Costs 5,054,000    
Net Proceeds $ 147,446,000    
Coupon rate 7.75%    
Effective interest rate 8.04%