Schedule II-Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for doubtful accounts
Changes in valuation and qualifying accounts
Balance at Beginning of Year	$ 1.0	$ 0.7	$ 0.5
Additions Charged to Costs and Expenses	0.7	0.7	0.6
Reductions	(0.8)	(0.5)	(0.4)
Balance at End of Year	0.9	1.0	0.7
Tax valuation account
Changes in valuation and qualifying accounts
Balance at Beginning of Year	12.3	21.3	25.3
Additions Charged to Costs and Expenses	0.0	0.0	2.1
Reductions	(5.5)	(9.0)	(6.0)
Balance at End of Year	$ 6.8	$ 12.3	$ 21.3