Supplemental Cash Flow Information - Schedule of Supplemental Cash Flow Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash paid for interest:
Interest paid for continuing operations	$ 31.5	$ 16.7
Interest paid for discontinued operations	0.0		$ 0.8
Continuing Operations
Cash paid for income taxes:
Income taxes paid	3.8	$ 4.3	0.5
Discontinued Operations
Cash paid for income taxes:
Income taxes paid	$ 0.0		$ 0.1