Income Taxes - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) Assets	Dec. 31, 2014 USD ($)
Income Taxes [Line Items]
Percentage of distributed taxable income to qualify as a REIT	90.00%
Number of years the Company distributed sufficient taxable income in order to meet REIT distribution requirements	3 years
U.S. federal income taxes	$ 0	$ 0	$ 0
U.S. federal excise taxes	$ 0	0	0
Number of subsequent taxable years	4 years
Tax cost basis of assets	$ 9,800,000,000	10,600,000,000
Net payment	1,000,000	1,500,000	1,600,000
Tax expense	1,781,000	$ 6,286,000	$ 1,855,000
Puerto Rico [Member]
Income Taxes [Line Items]
Number of properties | Assets		14
Prepay of taxes		$ 20,200,000
Prepaid expenses	$ 16,200,000	16,800,000
Tax expense		$ 3,400,000
Effective tax rate spread		2.00%
Effective tax rate		12.00%	0.00%
Withholding tax rate		10.00%
Effective tax rate on capital gains		12.00%	29.00%