Acquisitions - Assets (Liabilities) Acquired (Assumed) at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tangible assets (liabilities) acquired (assumed):
Goodwill	$ 483,634	$ 413,123	$ 386,941
Cash paid for acquisitions	100,117	47,571	$ 48,418
2021 Acquisitions
Tangible assets (liabilities) acquired (assumed):
Accounts receivable, net	601
Inventories, net	27,746
Prepaid expenses and other assets	125
Property and equipment, net	1,348
Operating lease assets	1,222
Accrued liabilities	(214)
Operating lease liabilities - current	(195)
Operating lease liabilities - noncurrent	(1,027)
Total tangible net assets acquired	29,606
Goodwill	70,511
Cash paid for acquisitions	100,117
Inventory purchases financed via floor plan	(19,537)
Cash payment net of floor plan financing	$ 80,580
2020 Acquisitions
Tangible assets (liabilities) acquired (assumed):
Accounts receivable, net		3,094
Inventories, net		17,211
Prepaid expenses and other assets		643
Property and equipment, net		1,077
Operating lease assets		1,859
Finance lease asset		2,373
Accounts payable		(1,628)
Accrued liabilities		(2,839)
Operating lease liabilities - current		(212)
Operating lease liabilities - noncurrent		(1,647)
Finance lease liabilities - current		(179)
Finance lease liabilities - noncurrent		(2,194)
Total tangible net assets acquired		17,558
Intangible assets		3,832
Goodwill		26,182
Cash paid for acquisitions		47,572
Inventory purchases financed via floor plan		(10,350)
Cash payment net of floor plan financing		37,222
2020 Acquisitions | Trademarks and trade names
Tangible assets (liabilities) acquired (assumed):
Intangible assets		725
2020 Acquisitions | Supplier And customer relationships
Tangible assets (liabilities) acquired (assumed):
Intangible assets		$ 3,107