BASIC AND DILUTED EARNINGS (LOSS) PER COMMON SHARE - Components of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Income from continuing operations, net of taxes	$ 26.2	$ 7.9	$ 26.0	$ (0.8)	$ 2.3	$ 14.2	$ 14.4	$ 8.7	$ 59.3	$ 39.6	$ 24.6
(Loss) Income from discontinued operations, net of taxes	(1.4)	(1.7)	0.0	(0.1)	0.4	0.4	3.7	(3.2)	(3.2)	1.3	(30.4)
Net income (loss)	$ 24.8	$ 6.2	$ 26.0	$ (0.9)	$ 2.7	$ 14.6	$ 18.1	$ 5.5	$ 56.1	$ 40.9	$ (5.8)
Denominator:
Weighted average common shares outstanding - Basic (shares)									52,431,193	52,359,897	52,356,798
Effect of dilutive restricted stock (shares)									160,352	64,042	931
Weighted average common shares outstanding - Diluted (shares)									52,591,545	52,423,939	52,357,729
Basic earnings (loss) per common share:
Continuing operations (usd per share)	$ 0.50	$ 0.15	$ 0.50	$ (0.02)	$ 0.04	$ 0.27	$ 0.27	$ 0.17	$ 1.13	$ 0.76	$ 0.47
Discontinued operations (usd per share)	(0.03)	(0.03)	0.00	0.00	0.01	0.01	0.07	(0.06)	(0.06)	0.02	(0.58)
Net income (usd per share)	0.47	0.12	0.50	(0.02)	0.05	0.28	0.34	0.11	1.07	0.78	(0.11)
Diluted earnings (loss) per common share:
Continuing operations (usd per share)	0.50	0.15	0.49	(0.02)	0.04	0.27	0.27	0.17	1.13	0.76	0.47
Discontinued operations (usd per share)	(0.03)	(0.03)	0.00	0.00	0.01	0.01	0.07	(0.06)	(0.06)	0.02	(0.58)
Net income (usd per share)	$ 0.47	$ 0.12	$ 0.49	$ (0.02)	$ 0.05	$ 0.28	$ 0.34	$ 0.11	$ 1.07	$ 0.78	$ (0.11)