XML 50 R39.htm IDEA: XBRL DOCUMENT v3.7.0.1
Financial Instruments - Schedule of Changes in Fair Value of Financial Assets and Liabilities Classified as Level 3 (Detail) - Significant Unobservable Inputs (Level 3) [Member]
$ in Thousands
6 Months Ended
Jun. 30, 2017
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Net (liabilities) assets at beginning of period $ (3,582)
Total realized and unrealized (gains) losses:  
Included in earnings 4,149 [1]
Purchases, sales, issuances and settlements 205
Net (liabilities) assets at end of period $ 772
[1] Derivative instruments are reported in revenues as realized gain/loss and on a separately reported line item captioned unrealized gain/loss on derivative instruments, and interest rate swap instruments are reported as an increase or reduction to interest expense.