BASIC AND DILUTED EARNINGS 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, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Numerator:
(Loss) income from continuing operations, net of taxes	$ (77.7)	$ (32.8)	$ (37.1)	$ (37.7)	$ (33.9)	$ (4.5)	$ 10.8	$ 10.6	$ (185.3)	$ (17.0)		$ 59.3
Income (loss) from discontinued operations, net of taxes	0.8	0.4	0.6	0.3	(2.6)	(0.2)	(2.5)	0.4	2.1	(4.9)		(3.2)
Net (loss) income	$ (76.9)	$ (32.4)	$ (36.5)	$ (37.4)	$ (36.5)	$ (4.7)	$ 8.3	$ 11.0	$ (183.2)	$ (21.9)	[1]	$ 56.1	[1]
Denominator:
Weighted average common shares outstanding - Basic (shares)									52,597,582	52,504,196		52,431,193
Effect of dilutive restricted stock (shares)									0	0		160,352
Weighted average common shares outstanding - Diluted (shares)									52,597,582	52,504,196		52,591,545
Basic (loss) earnings per common share:
Continuing operations (usd per share)	$ (1.48)	$ (0.62)	$ (0.70)	$ (0.72)	$ (0.65)	$ (0.09)	$ 0.21	$ 0.20	$ (3.52)	$ (0.33)		$ 1.13
Discontinued operations (usd per share)	0.02	0.01	0.00	0.01	(0.05)	0.00	(0.05)	0.01	0.04	(0.09)		(0.06)
Net (loss) income (usd per share)	(1.46)	(0.61)	(0.70)	(0.71)	(0.70)	(0.09)	0.16	0.21	(3.48)	(0.42)		1.07
Diluted (loss) earnings per common share:
Continuing operations (usd per share)	(1.48)	(0.62)	(0.70)	(0.72)	(0.65)	(0.09)	0.21	0.20	(3.52)	(0.33)		1.13
Discontinued operations (usd per share)	0.02	0.01	0.00	0.01	(0.05)	0.00	(0.05)	0.01	0.04	(0.09)		(0.06)
Net (loss) income (usd per share)	$ (1.46)	$ (0.61)	$ (0.70)	$ (0.71)	$ (0.70)	$ (0.09)	$ 0.16	$ 0.21	$ (3.48)	$ (0.42)		$ 1.07
Restricted Stock
Diluted (loss) earnings per common share:
Unvested restricted stock awards under the Stock Plan (shares)									20,804	109,481		0

[1] Adjusted as a result of the adoption of certain accounting pronouncements beginning on January 1, 2017. See Note 1, "Description of Business and Summaryof Significant Accounting Policies - Recently Adopted Accounting Pronouncements," for details of these adjustments.