Inventories, Contracts in Progress and Vehicle Floor Plan Payable (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Inventory [Line Items]
Weighted average interest rate	4.80%	5.00%	4.90%	5.10%
Automotive [Member]
Inventory [Line Items]
Borrowing capacity	$ 50,000,000		$ 50,000,000
Vehicle floor plan payable	10,900,000		10,900,000
Floor plan assistance	$ 700,000	$ 600,000	$ 2,100,000	$ 1,500,000
Automotive [Member] | Vehicle Floor Plan Facility [Member]
Inventory [Line Items]
Weighted average interest rate	0.90%	1.20%	1.10%	1.90%
London Interbank Offered Rate (LIBOR) [Member] | Automotive [Member] | Vehicle Floor Plan Facility [Member]
Inventory [Line Items]
Applicable interest rate margin			1.15%