Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Minimum Distribution Percentage of Taxable Income to Qualify for Real Estate Investment Trust		90.00%
TCJA enacted date		Dec. 22, 2017
U.S. federal corporate tax rate		35.00%	35.00%	35.00%
TCJA one time transition tax		$ 0
Effect of change in income tax associated with the ACT		4,500,000
Tax benefits associated with equity-based compensation			$ 1,479,000	$ 525,000
Reduction in income taxes payable		$ (948,000)	$ (1,645,000)	$ (1,077,000)
Effective tax rate		7.20%	3.60%	3.60%
Liabilities for uncertain tax positions		$ 0	$ 0
Accounting Standards Update 2016-09
Income Taxes [Line Items]
Reduction in income taxes payable		$ 1,000,000
Scenario Forecast
Income Taxes [Line Items]
U.S. federal corporate tax rate	21.00%