XML 50 R40.htm IDEA: XBRL DOCUMENT v3.8.0.1
Derivative Instruments and Hedging Activities - Effect of Derivative Instruments on the Condensed Consolidated Statement of Operations (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Cash received (paid) on settlement of derivative instruments, gain (loss) on derivative instruments $ (26,131) $ (1,524)
Non-cash gain (loss) on derivative instruments, gain (loss) on derivative instruments 31,708 34,908
Gain (loss) on derivative instruments $ 5,577 $ 33,384