Real Estate and Lease Intangibles - Real Estate Acquisitions and Dispositions (Parenthetical) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Property	Dec. 31, 2016 USD ($) Property
Real Estate [Line Items]
Purchase Price | $	$ 468,050	$ 249,334
Properties disposed | Property	5	99
Disposed Units | Property	1,194	29,776
Sales Price | $	$ 388,400	$ 6,943,458
Unconsolidated Rental Properties [Member]
Real Estate [Line Items]
Properties disposed | Property		1
Disposed Units | Property		336
Sales Price | $		$ 74,500
Equity Method Investment, Ownership Percentage		20.00%
Distributions from unconsolidated entities - return of capital | $		$ 12,400
Starwood Portfolio [Member]
Real Estate [Line Items]
Properties disposed | Property		72
Disposed Units | Property		23,262
Sales Price | $		$ 5,365,000
Land [Member]
Real Estate [Line Items]
Purchase Price | $	$ 68,300	$ 98,000
Properties disposed | Property	0	0
Disposed Units | Property	0	0
Sales Price | $	$ 33,450	$ 57,455
Depreciable Property [Member]
Real Estate [Line Items]
Purchase Price | $	386,200	151,300
Rental Properties – Consolidated [Member]
Real Estate [Line Items]
Purchase Price | $	$ 468,050	$ 249,334
Properties disposed | Property	5	98
Disposed Units | Property	1,194	29,440
Sales Price | $	$ 354,950	$ 6,811,503
Rental Properties – Consolidated [Member] | Starwood Portfolio [Member]
Real Estate [Line Items]
Properties disposed | Property		72
Disposed Units | Property		23,262
Sales Price | $		$ 5,365,000
Rental Properties – Consolidated [Member] | Ground Lease [Member] | Other Assets [Member]
Real Estate [Line Items]
Finite-Lived Intangible Asset, Off-market Lease, Favorable, Gross | $	$ 13,700
Lease expiration year	2113