Segment Information - Additional Information (Details) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) segment	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment information
Number of reportable segments (segment) | segment				2
Total revenues		$ 313,024	$ 301,116	$ 617,279	$ 602,811
Net income		173,741	115,899	226,510	229,722
Total assets	[1]	13,629,941		13,629,941		$ 12,751,358
Marketing, general and administrative		25,480	22,479	51,459	46,007
Operating Segments | Real Estate Segment
Segment information
Total revenues		261,406	251,843	515,630	508,248
Net income		140,934	81,755	162,506	161,790
Total assets		11,308,533		11,308,533		10,481,594
Operating Segments | Debt and Preferred Equity Segment
Segment information
Total revenues		51,618	49,273	101,649	94,563
Net income		32,807	$ 34,144	64,004	$ 67,932
Total assets		$ 2,321,408		$ 2,321,408		$ 2,269,764

[1] The Company's consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs"). See Note 2. The consolidated balance sheets include the following amounts related to our consolidated VIEs, excluding the Operating Partnership: $219.4 million and $110.0 million of land, $0.5 billion and $0.3 billion of building and improvements, $2.0 million and $2.0 million of building and leasehold improvements, $61.7 million and $47.4 million of right of use assets, $21.4 million and $42.2 million of accumulated depreciation, $86.1 million and $112.6 million of other assets included in other line items, $461.7 million and $140.8 million of real estate debt, net, $1.5 million and $0.4 million of accrued interest payable, $57.1 million and $43.6 million of lease liabilities, and $50.4 million and $18.3 million of other liabilities included in other line items as of June 30, 2019 and December 31, 2018, respectively.