Equity Investments in the Managed Programs and Real Estate - Equity Method Investments Excluding the Managed Programs (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Investments in Programs
Equity investments in real estate	$ 276,109	$ 324,004
Real Estate
Investments in Programs
Equity investments in real estate	$ 190,728	194,437
Real Estate | Third Party | Kesko Senukai
Investments in Programs
Equity method investment, ownership percentage	70.00%
Equity investments in real estate	$ 45,803	46,475
Real Estate | Third Party | BPS Nevada, LLC
Investments in Programs
Equity method investment, ownership percentage	15.00%
Equity investments in real estate	$ 22,904	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	$ 70,309	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	$ 26,107	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	$ 16,781	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	$ 5,906	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	$ 2,918	$ 2,712