Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Jan. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred tax assets, gross	$ 131.2		$ 138.3
Valuation allowance	114.1		114.2
Estimated recoverable deferred income tax assets	$ 17.1		$ 24.1
Percentage of probability of deferred income tax realized in future	50.00%
Valuation allowance, methodologies and assumptions	"more likely than not" (greater than a 50% probability)
Federal income tax at statutory rate	35.00%
Approximate Federal net operating losses ("NOLs") available to offset future taxable income	$ 308.1
Limited net operating losses rate under "IRC Section 382"		$ 119.6
Allowable net operating losses utilize per year under "IRC Section 382"		$ 6.1