Leases - Summary of Revenue from Master Lease (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Property Subject to or Available for Operating Lease [Line Items]
Rental income	$ 41,152	$ 48,167	$ 114,070	$ 139,526
Total revenue	56,593	64,048	159,640	187,339
Master Lease [Member]
Property Subject to or Available for Operating Lease [Line Items]
Rental income	21,413	27,889	66,548	88,748
Termination fee income	6,988	10,596	7,162	17,361
Tenant reimbursements	10,810	10,639	35,028	38,370
Total revenue	$ 39,211	$ 49,124	$ 108,738	$ 144,479