Reorganization and Fresh Start Accounting - Fresh Start Adjustment, Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Feb. 05, 2021	Dec. 31, 2020
Reorganization, Chapter 11 [Line Items]
Common stock	$ 1	$ 1	$ 2,511
Additional paid-in capital	1,388,388	1,018,767	814,796
Intangible assets	76,262	113,389	0
Property and equipment, net	1,462,075	1,155,725	3,577,069
Long-term debt	406,000	393,500	0
Deferred income taxes	13,568	21,525	9,292
Accumulated other comprehensive income (loss)	$ (267)	0	$ (58,012)
Fresh Start Adjustments
Reorganization, Chapter 11 [Line Items]
Intangible assets		113,389
Property and equipment, net		(2,410,903)
Long-term debt		41,446
Deferred income taxes		29,550
Accumulated other comprehensive income (loss)		$ 57,904

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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