Subsequent Events (Details) - Revolving Credit Facility - Line of Credit - USD ($)
May 04, 2018
Nov. 02, 2017
Mar. 31, 2018
Subsequent Event [Line Items]      
Borrowing base     $ 575,000,000
Elected commitments     $ 475,000,000
Commitment fee percentage   0.50%  
Subsequent Event      
Subsequent Event [Line Items]      
Borrowing base $ 800,000,000    
Elected commitments $ 600,000,000    
Line of credit, term 5 years    
Minimum | Subsequent Event      
Subsequent Event [Line Items]      
Commitment fee percentage 0.375%    
Minimum | LIBOR      
Subsequent Event [Line Items]      
Basis spread on variable rate   2.25%  
Minimum | LIBOR | Subsequent Event      
Subsequent Event [Line Items]      
Basis spread on variable rate 1.50%    
Minimum | Base Rate      
Subsequent Event [Line Items]      
Basis spread on variable rate   1.25%  
Minimum | Base Rate | Subsequent Event      
Subsequent Event [Line Items]      
Basis spread on variable rate 0.50%    
Maximum | Subsequent Event      
Subsequent Event [Line Items]      
Commitment fee percentage 0.50%    
Maximum | LIBOR      
Subsequent Event [Line Items]      
Basis spread on variable rate   3.25%  
Maximum | LIBOR | Subsequent Event      
Subsequent Event [Line Items]      
Basis spread on variable rate 2.50%    
Maximum | Base Rate      
Subsequent Event [Line Items]      
Basis spread on variable rate   2.25%  
Maximum | Base Rate | Subsequent Event      
Subsequent Event [Line Items]      
Basis spread on variable rate 1.50%