Schedule of Activity Related to Redeemable Preferred Stock (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Debt Disclosure [Abstract]
Balance, December 31, 2015			$ 21.9
Dividends on Redeemable Preferred Stock, in-kind	$ 0.5	$ 0.5	0.9	$ 0.6
Accretion of fair value adjustment to Redeemable Preferred Stock	0.2	$ 0.2	0.5	$ 0.3
Balance, June 30, 2016	$ 23.3		$ 23.3