Leases - Summary of Fixed and Variable Components of Operating Leases (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Fixed ground rent expense	$ 1,000	$ 390	$ 3,026	$ 1,108
Variable ground rent expense			18	21
Total cash portion of ground rent expense	1,000	390	3,044	1,129
Non-cash ground rent expense	1,656	1,091	5,090	3,275
Total operating lease costs	$ 2,656	$ 1,481	$ 8,134	$ 4,404