Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts Receivable
Valuation and Qualifying Accounts and Reserves
Balance at beginning of period	$ 1.1	$ 0.7	$ 0.9
Charged to costs and expenses		0.6
Deductions/Applications	(0.6)	0.2	0.2
Balance at end of period	0.5	1.1	0.7
Notes issued under par
Valuation and Qualifying Accounts and Reserves
Balance at beginning of period	60.5	62.2	63.8
Charged to costs and expenses	1.7	1.7	1.6
Balance at end of period	58.8	60.5	$ 62.2
Valuation allowance
Valuation and Qualifying Accounts and Reserves
Balance at beginning of period	619.6
Charged to costs and expenses	199.5	619.6
Balance at end of period	$ 819.1	$ 619.6