Leases - Schedule of Future Lease Payments Due Under Ground Leases (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Operating Leases
2019 (remaining)	$ 742
2020	1,445
2021	1,481
2022	1,518
2023	1,556
2024	1,596
Thereafter	457,749
Total undiscounted future lease payments	466,087
Difference between undiscounted cash flows and discounted cash flows	434,373
Total lease liability	31,714
Financing Leases
2019 (remaining)	1,474
2020	2,991
2021	3,081
2022	3,174
2023	3,269
2024	3,367
Thereafter	330,546
Total undiscounted future lease payments	347,902
Difference between undiscounted cash flows and discounted cash flows	291,632
Total lease liability	$ 56,270	$ 4,300