Quarterly report pursuant to Section 13 or 15(d)

Borrowings (Credit Facility) (Narrative) (Details)

v3.7.0.1
Borrowings (Credit Facility) (Narrative) (Details) - Senior Secured Revolving Credit Facility [Member]
$ in Thousands
3 Months Ended
Mar. 31, 2017
USD ($)
Line of Credit Facility [Line Items]  
Maximum borrowing capacity $ 500,000
Credit facility borrowing base $ 385,000
Credit facility maturity date Mar. 11, 2019
Balance outstanding on credit facility $ 0
Interest rate at period end (as a percent) 2.83%
Unused capacity, commitment fee (as a percent) 0.50%
Minimum [Member]  
Line of Credit Facility [Line Items]  
Debt instrument interest rate 2.00%
Maximum [Member]  
Line of Credit Facility [Line Items]  
Debt instrument interest rate 3.00%