Annual report pursuant to Section 13 and 15(d)

Derivative Instruments - Schedule of Derivative Instruments in Statement of Financial Position (Details)

v3.10.0.1
Derivative Instruments - Schedule of Derivative Instruments in Statement of Financial Position (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Short-term derivative instruments - asset $ 21,352 $ 78,847
Long-term derivative instruments 0 8,685
Short-term derivative instruments - liability 20,401 32,534
Long-term derivative instruments - liability $ 13,992 $ 2,989