Summary of Significant Accounting Policies - Real Estate-Related Securities (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) investment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Debt Securities, Available-for-sale [Line Items]
Sale price	$ 258,260,000	$ 37,083,000
Proceeds from sale of CMBS	256,841,000	37,593,000
Gain on sale of CMBS	(1,419,000)	510,000
Real estate-related securities ($41,981 and $38,194 held at fair value as of December 31, 2021 and December 31, 2020, respectively)	105,471,000	38,194,000	$ 0
Investments in marketable securities	110,000
Allowance for credit losses			$ 0
Capitalized interest income on real estate-related securities	974,000	0
Level 3
Debt Securities, Available-for-sale [Line Items]
Net investments in debt securities	257,700,000
Sale price	257,800,000
Proceeds from sale of CMBS	256,400,000
Gain on sale of CMBS	$ (1,400,000)
Number of investments | investment	2
Real estate-related securities ($41,981 and $38,194 held at fair value as of December 31, 2021 and December 31, 2020, respectively)	$ 41,900,000
Allowance for credit losses	0	$ 0
Preferred units
Debt Securities, Available-for-sale [Line Items]
Net investments in debt securities	63,500,000
Real estate-related securities ($41,981 and $38,194 held at fair value as of December 31, 2021 and December 31, 2020, respectively)	$ 63,490,000
Preferred stock, dividend rate	8.90%