Real Estate - Schedule of Property Dispositions (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on Sale		$ 28,815	$ 4,612
Disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale Price	[1]	113,114		$ 66,325
Gain on Sale	[1]	$ 28,815		$ 9,787
Core Portfolio | Disposed of by sale | 60 Orange St - Bloomfield, NJ.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date Sold				Jan. 29, 2021
Sale Price				$ 16,400
Gain on Sale				$ 4,612
Fund IV | Disposed of by sale | NE Grocer Portfolio (Selected Assets) - Pennsylvania
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date Sold		Jan. 26, 2022
Sale Price		$ 45,350
Gain on Sale		$ 13,784
Fund IV | Disposed of by sale | NE Grocer Portfolio (Selected Assets) - Maine
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date Sold				Jun. 18, 2021
Sale Price				$ 39,925
Gain on Sale				$ 5,064
Fund III | Disposed of by sale | Cortlandt Crossing - Westchester County, New York
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date Sold		Feb. 09, 2022
Sale Price		$ 65,533
Gain on Sale		$ 13,255
Fund III | Disposed of by sale | 654 Broadway - New York, NY
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date Sold				May 19, 2021
Sale Price				$ 10,000
Gain on Sale				$ 111
Fund V | Disposed of by sale | New Towne (Parcel) - Canton, MI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date Sold		Feb. 01, 2022
Sale Price		$ 2,231
Gain on Sale		$ 1,776

[1] Does not include the g