Equity Investments in the Managed Programs and Real Estate - Equity Method Investments Excluding the Managed Programs (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Investments in Programs
Equity investments in real estate	$ 284,643	$ 324,004
Real Estate
Investments in Programs
Equity investments in real estate	$ 235,744	194,437
Real Estate | Third Party | Kesko Senukai
Investments in Programs
Equity method investment, ownership percentage	70.00%
Equity investments in real estate	$ 41,807	46,475
Real Estate | Third Party | BPS Nevada, LLC
Investments in Programs
Equity method investment, ownership percentage	15.00%
Equity investments in real estate	$ 23,040	22,900
Real Estate | Third Party | Affiliated Entity | Johnson Self Storage
Investments in Programs
Equity method investment, ownership percentage	90.00%
Equity investments in real estate	$ 69,823	70,690
Real Estate | CPA:18 – Global | Affiliated Entity | Bank Pekao S.A.
Investments in Programs
Equity method investment, ownership percentage	50.00%
Equity investments in real estate	$ 25,906	26,388
Real Estate | CPA:18 – Global | Affiliated Entity | State Farm Mutual Automobile Insurance Co.
Investments in Programs
Equity method investment, ownership percentage	50.00%
Equity investments in real estate	$ 16,343	17,232
Real Estate | CPA:18 – Global | Affiliated Entity | Apply Sorco AS
Investments in Programs
Equity method investment, ownership percentage	49.00%
Equity investments in real estate	$ 6,692	8,040
Real Estate | CPA:18 – Global | Affiliated Entity | Fortenova Grupa d.d.( formerly Konzum d.d.)
Investments in Programs
Equity method investment, ownership percentage	20.00%
Equity investments in real estate	$ 2,923	2,712
Real Estate | WLT | Affiliated Entity | WLT
Investments in Programs
Equity method investment, ownership percentage	5.00%
Equity investments in real estate	$ 49,210	$ 0