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Chapter 11 Cases and Ability to Continue as a Going Concern - Narrative (Details) - USD ($) $ in Thousands				3 Months Ended	12 Months Ended
	Mar. 21, 2021	Nov. 02, 2020	Aug. 18, 2020	Mar. 31, 2021	Dec. 31, 2020
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Secured credit facility				$ 3,394,879
Reorganization items				22,933
Professional fees				22,230
U.S. Trustee fees				703
Liabilities subject to compromise				2,551,354	$ 2,551,490
Interest expense				$ 44,764
Series D Preferred Stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend rate of preferred stock (as a percent)		7.375%		7.375%	7.375%
Series E Preferred Stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Dividend rate of preferred stock (as a percent)		6.625%		6.625%	6.625%
Senior Unsecured Notes
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Liabilities subject to compromise				$ 1,375,000	$ 1,375,000
Secured Line of Credit
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Liabilities subject to compromise				675,926	675,926
Secured Term Loan
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Liabilities subject to compromise				438,750	438,750
Unpaid Accrued Interest
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Liabilities subject to compromise				57,644	57,644
Prepetition Unsecured Or Under Secured Liabilities
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Liabilities subject to compromise				$ 4,034	$ 4,170
Restructuring Support Agreement
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Aggregate outstanding principal amount of debt	96.00%
Elimination of debt as result of implementation of plan	$ 1,681,900
Principal amount of unsecured notes	1,375,000
New senior secured notes	555,000
Cash	95,000
Convertible secured notes	$ 100,000
Percentage of issuance of new common equity to holders of unsecured notes	89.00%
Restructuring Support Agreement \| Secured Credit Facility
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Secured credit facility	$ 133,000
Restructuring Support Agreement \| Subscription Option
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Cash	100,000
Convertible secured notes	$ 50,000
Percentage of issuance of new common equity to holders of unsecured notes	11.00%
Restructuring Support Agreement \| Subscription Option \| Secured Credit Facility
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Secured credit facility	$ 983,700
Restructuring Support Agreement \| Subscription Option \| Secured Term Loan
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Secured credit facility	$ 883,700
Restructuring Support Agreement \| Senior Unsecured Notes \| 2023 Notes
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Aggregate principal amount of senior unsecured notes			$ 450,000
Interest rate percentage			5.25%
Debt instrument, maturity date			Dec. 01, 2023
Restructuring Support Agreement \| Senior Unsecured Notes \| 2024 Notes
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Aggregate principal amount of senior unsecured notes			$ 300,000
Interest rate percentage			4.60%
Debt instrument, maturity date			Oct. 15, 2024
Restructuring Support Agreement \| Senior Unsecured Notes \| 2026 Notes
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Aggregate principal amount of senior unsecured notes			$ 625,000
Interest rate percentage			5.95%
Debt instrument, maturity date			Dec. 15, 2026
Minimum \| Restructuring Support Agreement
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Aggregate principal amount of operating partnership	69.00%		62.00%