Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Corporate income tax rate (as a percent)									21.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Statutory federal income tax provision									$ (58,047)	$ (44,431)	$ (56,914)
Adjustment for nontaxable income of the REIT									50,075	38,272	48,680
State taxes (net of federal tax benefit)									(4,268)	(1,317)	(1,705)
Permanent share-based compensation adjustment									821	1,446	1,571
Other permanent items									(46)	(251)	(200)
Valuation allowance reversal					$ 53,400				53,400
Effect of federal tax law change					2,000					2,030
Other									(238)	9	(123)
Total (provision) benefit for income taxes	$ (1,997)	$ (1,863)	$ (5,676)	$ (2,209)	$ 51,177	$ (530)	$ (899)	$ (593)	(11,745)	49,155	(3,400)
Domestic Tax Authority [Member]
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Valuation allowance reversal									46	36,156	5,519
State and Local Jurisdiction [Member]
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Valuation allowance reversal									$ (88)	$ 17,241	$ (228)