Income Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2013	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax Credit Carryforward [Line Items]
Annual distribution of net taxable income for U.S. federal income tax not to apply to our earnings that we distribute (percent)			90.00%
Net taxable income subject to distribution (percent)			100.00%
Excise tax rate			4.00%
Income tax provision			$ 314,000	$ 196,000	$ 504,000
Deferred tax assets			0	0
Deferred tax liabilities			$ 0	$ 0
U.S. federal corporate income tax rate			35.00%
Common stock, shares issued	25,875,000		12,421,401	1,070	34,780,622
Net operating losses carried forward			$ 159,000,000
NOLs expiration date			Dec. 31, 2029
Scenario, Forecast [Member]
Tax Credit Carryforward [Line Items]
U.S. federal corporate income tax rate		21.00%
Internal Revenue Service [Member]
Tax Credit Carryforward [Line Items]
Net operating losses limitations			The availability of our NOLs is generally limited to $2.0 million per annum
Earliest Tax Year [Member]
Tax Credit Carryforward [Line Items]
Open tax year			2014
Latest Tax Year [Member]
Tax Credit Carryforward [Line Items]
Open tax year			2017