Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 6.3	$ 7.9	$ 9.8
Additions charged to cost and expenses	2.4	2.8	2.6
Write-offs	(2.7)	(4.9)	(4.6)
Recoveries	0.9	1.1	1.1
Other	(0.2)	(0.6)	(1.0)
Balance at end of year	$ 6.7	$ 6.3	$ 7.9