Income Taxes - Details of Provision for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
U.S. Federal benefit	$ (0.1)	$ (0.1)
State and local tax	0.1	0.1	$ 0.1
Total current			0.1
Deferred:
U.S. Federal tax	(16.4)
State and local tax	(0.8)
Total deferred	(17.2)
Total income tax	$ (17.2)	$ 0.0	$ 0.1