Inventories, Contracts in Progress and Vehicle Floor Plan Payable (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Inventory [Line Items]
Weighted average interest rate	5.10%	6.20%
Automotive [Member]
Inventory [Line Items]
Borrowing capacity	$ 40,000,000
Vehicle floor plan payable	35,300,000
Floor plan assistance	$ 400,000
Automotive [Member] | Vehicle Floor Plan Facility [Member]
Inventory [Line Items]
Weighted average interest rate	3.50%
London Interbank Offered Rate (LIBOR) [Member] | Automotive [Member] | Vehicle Floor Plan Facility [Member]
Inventory [Line Items]
Applicable interest rate margin	1.15%