Loans to and Investments In Associated Companies (Garcadia) (Narrative) (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($) Dealership	Sep. 30, 2018 USD ($) Dealership
Garcadia
Investments In Associated Companies [Line Items]
Number of automobile dealerships	28	28
Plan One | Garcadia
Investments In Associated Companies [Line Items]
Percentage of cash flows allocated from joint venture		65.00%
Plan One | Garff Enterprises, Inc
Investments In Associated Companies [Line Items]
Percentage of cash flows allocated from joint venture		35.00%
Plan Two | Garcadia
Investments In Associated Companies [Line Items]
Number of automobile dealerships	1	1
Percentage of cash flows allocated from joint venture		83.00%
Plan Three | Garcadia
Investments In Associated Companies [Line Items]
Number of automobile dealerships	4	4
Percentage of cash flows allocated from joint venture		71.00%
Garcadia | Held-for-sale, not discontinued operations
Investments In Associated Companies [Line Items]
Percentage of equity method investment for sale	100.00%
Proceeds from sale of equity method investments and associated real estate | $	$ 417.2
Pre-tax gain on sale of equity method investments and associated real estate | $	$ 221.7	$ 221.7