Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	May. 31, 2013
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 (benefit)	$ 81,000	$ (118,000)	$ 431,000	$ 412,000
Deferred tax assets	0		0		$ 0
Deferred tax liabilities	0		$ 0		0
Net operating losses carried forward					159,000,000
Net capital losses carried forward					$ 32,000,000
NOLs expiration date			Expire in 2029
Capital Loss Carryforwards Expiring 2015 [Member]
Tax Credit Carryforward [Line Items]
Net capital losses carried forward	31,400,000		$ 31,400,000
Capital Loss Carryforwards Expiring 2016 [Member]
Tax Credit Carryforward [Line Items]
Net capital losses carried forward	602,000		602,000
Internal Revenue Service [Member]
Tax Credit Carryforward [Line Items]
Net operating losses and net capital losses	$ 2,000,000		$ 2,000,000
Class A Common Stock [Member]
Tax Credit Carryforward [Line Items]
Common stock, shares issued	93,212,863		93,212,863		58,269,889	25,875,000
Earliest Tax Year [Member]
Tax Credit Carryforward [Line Items]
Open tax year			2012
Latest Tax Year [Member]
Tax Credit Carryforward [Line Items]
Open tax year			2014