Derivative Instruments - Summary of Effects of Undesignated Derivatives on Consolidated Statements of Operations (Details) - Not Designated as Hedging Instrument [Member] - USD ($)
$ in Thousands |
3 Months Ended |
9 Months Ended |
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
| Interest Rate Contract [Member] | Change in Fair Value, Net of Settlement [Member] |
|
|
|
|
| Derivative Instruments, Gain (Loss) [Line Items] |
|
|
|
|
| Gain (loss) on undesignated derivatives, net |
$ 2,305
|
$ (7,570)
|
$ (10,513)
|
$ (5,264)
|
| Interest Rate Contract [Member] | Derivative Settlement [Member] |
|
|
|
|
| Derivative Instruments, Gain (Loss) [Line Items] |
|
|
|
|
| Gain (loss) on undesignated derivatives, net |
(1,272)
|
(1,383)
|
(3,878)
|
(3,302)
|
| Energy derivative [Member] | Change in Fair Value, Net of Settlement [Member] |
|
|
|
|
| Derivative Instruments, Gain (Loss) [Line Items] |
|
|
|
|
| Electricity sales |
(818)
|
4,630
|
(14,970)
|
1,600
|
| Energy derivative [Member] | Derivative Settlement [Member] |
|
|
|
|
| Derivative Instruments, Gain (Loss) [Line Items] |
|
|
|
|
| Electricity sales |
3,144
|
2,969
|
16,629
|
15,066
|
| Foreign currency forward contracts [Member] | Change in Fair Value, Net of Settlement [Member] |
|
|
|
|
| Derivative Instruments, Gain (Loss) [Line Items] |
|
|
|
|
| Gain (loss) on undesignated derivatives, net |
487
|
2,480
|
(4,128)
|
2,871
|
| Foreign currency forward contracts [Member] | Derivative Settlement [Member] |
|
|
|
|
| Derivative Instruments, Gain (Loss) [Line Items] |
|
|
|
|
| Gain (loss) on undesignated derivatives, net |
$ 305
|
$ 382
|
$ 834
|
$ 382
|