Equity Method Investments - Equity Method Investments Excluding the Managed Programs (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Investments in Programs
Equity method investments in real estate	$ 351,865	$ 283,446
Real Estate
Investments in Programs
Equity method investments in real estate	289,939	226,889
Real Estate | Third Party | Affiliated Entity | Las Vegas Retail Complex
Investments in Programs
Equity method investments in real estate	$ 85,147	0
Real Estate | Third Party | Affiliated Entity | Johnson Self Storage
Investments in Programs
Equity method investment, ownership percentage	90.00%
Equity method investments in real estate	$ 68,158	68,979
Real Estate | Third Party | Affiliated Entity | Kesko Senukai
Investments in Programs
Equity method investment, ownership percentage	70.00%
Equity method investments in real estate	$ 41,913	46,443
Real Estate | Third Party | Affiliated Entity | Harmon Retail Corner
Investments in Programs
Equity method investment, ownership percentage	15.00%
Equity method investments in real estate	$ 24,225	23,815
Real Estate | WLT | WLT
Investments in Programs
Equity method investment, ownership percentage	5.00%
Equity method investments in real estate	$ 35,694	44,182
Real Estate | CPA:18 – Global | Bank Pekao S.A.
Investments in Programs
Equity method investment, ownership percentage	50.00%
Equity method investments in real estate	$ 17,700	17,850
Real Estate | CPA:18 – Global | Affiliated Entity | State Farm Mutual Automobile Insurance Co.
Investments in Programs
Equity method investment, ownership percentage	50.00%
Equity method investments in real estate	$ 7,832	15,475
Real Estate | CPA:18 – Global | Affiliated Entity | Apply Sorco AS
Investments in Programs
Equity method investment, ownership percentage	49.00%
Equity method investments in real estate	$ 6,258	7,156
Real Estate | CPA:18 – Global | Affiliated Entity | Fortenova Grupa d.d.
Investments in Programs
Equity method investment, ownership percentage	20.00%
Equity method investments in real estate	$ 3,012	$ 2,989