Income Taxes - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017 USD ($) Entity	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Income Taxes [Line Items]
Percentage of ordinary taxable income to be distributed for real estate investment trust qualification	90.00%	90.00%	90.00%
Percentage of taxable income to be distributed for federal income tax assumption	100.00%
Amount of foreign losses before income taxes	$ 100,000	$ 23,500,000	$ 29,400,000
Amount of domestic income (loss) before income taxes	13,900,000	(1,400,000)	$ 7,100,000
U.S federal NOLs	68,200,000
U.S. state NOLs	51,400,000
U.S. federal and state capital loss carryforwards	$ 9,500,000
U.S. federal and state capital loss, expiration year	2022
U.S federal alternative minimum tax credits carry forward	$ 300,000
Tax credit description	Alternative minimum tax credits exceed regular tax liability in tax years 2018 through 2020
Percentage of credit refundable	50.00%
Foreign NOLs	$ 23,000,000
Cumulative pre-tax loss position period	3 years
Valuation allowance not expected to be realized	$ 6,800,000
Valuation allowance	$ 11,101,000	15,975,000
Number of existing foreign entities | Entity	11
Number of new foreign entities formed | Entity	7
Uncertain tax position liabilities and related interest or penalties	$ 0
Valuation Allowance of Deferred Tax Assets [Member]
Income Taxes [Line Items]
Valuation allowance		4,000,000
Valuation Allowance of Deferred Tax Assets Foreign [Member]
Income Taxes [Line Items]
Valuation allowance not expected to be realized	$ 4,300,000
Valuation allowance		$ 2,200,000
Maximum [Member]
Income Taxes [Line Items]
U.S. federal and state NOLs, expiration period	2035
Minimum [Member]
Income Taxes [Line Items]
U.S. federal and state NOLs, expiration period	2021