Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands		Sep. 30, 2021	Jul. 01, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jul. 01, 2020	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment		$ (7,218,797)		$ (7,351,410)	$ (7,289,950)	$ (7,362,191)		$ (7,637,256)		$ (6,658,859)
Redeemable noncontrolling interests		119,591			57,396
Accounts payable, accrued liabilities, and other liabilities		$ (729,939)			(760,617)
Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment			$ 82,319		54,622	44,117	$ 31,465			8,615
Redeemable noncontrolling interests			85,367		57,396	46,850	34,054			11,106
Accounts payable, accrued liabilities, and other liabilities			$ 3,048		$ 2,774	$ 2,733	$ 2,589			2,491
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment	[1]									$ 1,524
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment									$ (2,000)

[1] On January 1, 2020, the Company adopted a series of Accounting Standards Updates (“ASUs”) related to accounting for credit losses and recognized the cumulative-effect of adoption to beginning retained earnings. Refer to Note 2 for a detailed impact of adoption.