Derivative Instruments - Effect of Derivative Instruments on the Condensed Consolidated Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash received (paid) on settlement of derivative instruments, gain (loss) on derivative instruments	$ 15,397	$ 5,819	$ 68,377	$ (20,312)
Non-cash gain (loss) on derivative instruments, gain (loss) on derivative instruments	48,252	(9,487)	3,529	22,221
Gain (loss) on derivative instruments	$ 63,649	$ (3,668)	$ 71,906	$ 1,909

The realized gain (loss) on derivative instruments from the difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings.

No definition available.

+ Details

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

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- References

No definition available.

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

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