Assets and Liabilities of Discontinued Operations (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Current assets	$ 0.0	$ 0.3
Current liabilities		0.1
Noncurrent liabilities		0.7
Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Current assets	0.0	0.3
Current liabilities	0.0	0.1
Noncurrent liabilities	$ 0.0	$ 0.7