Segment Information - Additional Information (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) segment	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment information
Number of reportable segments (segment) | segment				2
Total revenues		$ 313,634	$ 307,545	$ 930,913	$ 910,356
Net income		40,722	99,454	267,232	329,176
Total assets	[1]	13,294,984		13,294,984		$ 12,751,358
Marketing, general and administrative		23,841	20,594	75,300	66,601
Operating Segments | Real Estate Segment
Segment information
Total revenues		262,115	258,568	777,745	766,816
Net income		6,133	62,199	168,639	224,246
Total assets		11,216,682		11,216,682		10,481,594
Operating Segments | Debt and Preferred Equity Segment
Segment information
Total revenues		51,519	48,977	153,168	143,540
Net income		34,589	$ 37,255	98,593	$ 104,930
Total assets		$ 2,078,302		$ 2,078,302		$ 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, $522.9 million and $346.7 million 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, $27.6 million and $42.2 million of accumulated depreciation, $99.4 million and $112.6 million of other assets included in other line items, $473.2 million and $140.8 million of real estate debt, net, $1.4 million and $0.4 million of accrued interest payable, $57.4 million and $43.6 million of lease liabilities, and $35.7 million and $18.3 million of other liabilities included in other line items as of September 30, 2019 and December 31, 2018, respectively.