Income Taxes - Reconciliation of Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2017
Reconciliation of statutory tax to effective tax
Federal statutory tax rate	$ 31,078	$ 37,711	$ 83,113	$ 54,231
REIT and other non-taxable loss	(24,527)	(24,688)	(73,046)	(41,697)
State income taxes	2,153	4,278	3,308	4,118
Federal benefit of state tax deduction	(452)	(899)	(695)	(865)
Net operating loss carryback rate differential	0	(1,569)	0	(5,286)
Intra-entity transfers	(312)	0	(6,364)	(3,781)
Other	(439)	10	62	96
Effective tax rate	$ 7,501	$ 14,843	$ 6,378	$ 6,816
Reconciliation of statutory tax rate to effective tax rate
Federal statutory tax rate	21.00%	21.00%	21.00%	21.00%	35.00%
REIT and other non-taxable loss	(16.60%)	(13.70%)	(18.50%)	(16.20%)
State income taxes	1.50%	2.40%	0.80%	1.60%
Federal benefit of state tax deduction	(0.30%)	(0.50%)	(0.20%)	(0.30%)
Net operating loss carryback rate differential	0.00%	(0.90%)	0.00%	(2.00%)
Intra-entity transfers	(0.20%)	0.00%	(1.50%)	(1.50%)
Other	(0.30%)	0.00%	0.00%	0.00%
Effective tax rate	5.10%	8.30%	1.60%	2.60%

Effective Income Tax Rate, Net Operating Loss Carryback Rate Differential

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to the federal benefit of state tax deductions.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operations attributable to deduction. Includes, but is not limited to, dividend deduction, deduction for dividend paid to employee stock ownership plan (ESOP), Medicare prescription drug benefit subsidy deduction, and other deductions.

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