Real Estate Investments, Net - Future Minimum Rental Revenues (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Future Minimum Rental Revenues
2019 (nine months)	$ 113,386
2020	151,591
2021	152,057
2022	152,541
2023	152,882
2024	153,150
Thereafter	988,982
Total	$ 1,864,589
Future Minimum Rental Revenues at Prior Year End
2019		$ 146,010
2020		146,560
2021		147,132
2022		147,719
2023		148,169
Thereafter		1,055,012
Total		$ 1,790,602