Investments in Real Estate - Schedule of Future Lease Payments Due Under Ground Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
2019 (remaining)	$ 1,059
2020	1,445
2021	1,481
2022	1,518
2023	1,556
2024	1,596
Thereafter	457,749
Total undiscounted future lease payments	466,404
Difference between undiscounted cash flows and discounted cash flows	434,921
Total right of use lease liability	31,483
Financing Leases
2019 (remaining)	2,189
2020	2,991
2021	3,081
2022	3,174
2023	3,269
2024	3,367
Thereafter	330,546
Total undiscounted future lease payments	348,617
Difference between undiscounted cash flows and discounted cash flows	288,309
Total right of use lease liability	$ 60,308	$ 4,300