Acquisitions and Dispositions of Businesses (Acquired assets and liabilities assumed) (Details 1) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill	$ 1,484,750	$ 1,388,279	$ 1,297,712
Floor plan payables		(25,800)
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Accounts receivable	745	6,762	2,344
Inventory	3,496	34,134	1,268
Property, plant and equipment	3,346	56,391	1,518
Lease right-of-use assets	6,580	98,505	0
Goodwill	73,951	84,669	41,840
Indefinite-lived intangible assets	0	46,900	0
Amortized intangible assets	14,589	21,291	78,427
Other assets	975	8,308	5,198
Floor plan payables	0	(25,755)	0
Other liabilities	(14,917)	(42,555)	(7,678)
Deferred income tax asset	15,958
Deferred income tax liability		(2,703)	(4,900)
Current and noncurrent lease liabilities	(6,593)	(99,131)	0
Redeemable noncontrolling interest	(6,005)	(1,715)	0
Noncontrolling interest	0	(1,154)	0
Aggregate purchase price, net of cash acquired	$ 92,125	$ 183,947	$ 118,017