Notes Payable and Amounts Due Under Repurchase Agreements (Repurchase Agreements Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Debt Disclosure [Abstract]
Repurchase agreement, average borrowings	$ 32.8	$ 20.4	$ 28.7	$ 54.6
Repurchase agreement, maximum amount borrowed			$ 186.4	$ 243.6
Repurchase agreement, weighted average interest rate	1.89%	4.62%	1.73%	3.04%