Real Estate, Operating Real Estate, Real Estate Under Construction, and Equity Investment in Real Estate - Placed Into Service (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Real Estate Properties
Total Capitalized Cost	$ 171,413	$ 236,923
Operating Real Estate | Austin, Texas | Operating Real Estate
Real Estate Properties
Total Capitalized Cost		78,927
Land, Buildings and Improvements
Real Estate Properties
Total Capitalized Cost	171,189	230,672
Land, Buildings and Improvements | Porto, Portugal (b) (d) | Real Estate
Real Estate Properties
Total Capitalized Cost	32,781
Land, Buildings and Improvements | Pamplona, Spain | Real Estate
Real Estate Properties
Total Capitalized Cost	35,096
Land, Buildings and Improvements | Swansea, United Kingdom (c) | Real Estate
Real Estate Properties
Total Capitalized Cost	46,593
Land, Buildings and Improvements | Bilbao, Spain | Real Estate
Real Estate Properties
Total Capitalized Cost	$ 56,719
Land, Buildings and Improvements | Barcelona, Spain (c) | Real Estate
Real Estate Properties
Total Capitalized Cost		33,429
Land, Buildings and Improvements | San Sebastian, Spain (c) | Real Estate
Real Estate Properties
Total Capitalized Cost		38,532
Land, Buildings and Improvements | Porto, Portugal (d) | Real Estate
Real Estate Properties
Total Capitalized Cost		28,809
Land, Buildings and Improvements | Malaga, Spain (d) | Real Estate
Real Estate Properties
Total Capitalized Cost		$ 50,975