Annual report pursuant to Section 13 and 15(d)

Derivative Contracts - Losses and Gains on Derivative Instruments (Details)

v3.6.0.2
Derivative Contracts - Losses and Gains on Derivative Instruments (Details) - Not Designated as Hedging Instrument - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative instruments $ 2,778 $ (39,083) $ (10,632)
Common stock options/warrants      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative instruments (4,262) (2,854) 1,193
2033 Senior Notes      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative instruments 7,001 (36,588) (12,213)
Forward contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) on derivative instruments $ 39 $ 359 $ 388