Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018
Provision for income tax	$ 238,000	$ 213,000
Percentage of rental income excluded from accounting standard adoption	94.00%
Percentage of total revenue subject to revenue recognition standard	6.00%
Right-of-use assets	$ 434,683,000		$ 434,201,000	$ 0
Lease liabilities	282,237,000		$ 278,287,000	$ 0
Federal [Member]
Provision for income tax	$ 0