Finance Receivables - Activity in allowance for credit losses (Parenthetical) (Details 1) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2020
Accounts Notes And Loans Receivable [Line Items]
Charge-offs	$ 6.4
Non-performing accounts
Accounts Notes And Loans Receivable [Line Items]
Charge-offs		$ 0.1
Bankruptcy
Accounts Notes And Loans Receivable [Line Items]
Charge-offs		$ 1.6