Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 114,887	$ 141,583	$ 139,062
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	177,347	175,484	185,122
(Gain) loss on sale of property and equipment, net	(1,852)	102	(297)
Stock-based compensation expense related to employee stock options and employee stock purchases	19,356	19,005	18,059
(Benefit) provision for deferred income tax expense	(37,858)	22,989	5,997
Change in accounts receivable, net	11,223	19,831	(7,746)
Change in inventories	536,682	81,722	(255,040)
Change in prepaid expenses and other, net	5,822	(10,237)	1,907
Change in trade accounts payable	(23,336)	2,241	18,490
(Payments) draws on floor plan notes payable – trade, net	(114,958)	(26,579)	76,646
Change in customer deposits	31,514	6,512	8,833
Change in accrued expenses	48,974	(12,757)	24,331
Other, net	(4,819)	1,376	0
Net cash provided by operating activities	762,982	421,272	215,364
Cash flows from investing activities:
Acquisition of property and equipment	(136,200)	(293,493)	(238,260)
Proceeds from the sale of property and equipment	5,783	2,310	6,325
Business acquisitions	0	(10,168)	0
Purchase of equity method investment and call option	0	(22,499)	0
Proceeds from the sale of available for sale securities	0	0	6,375
Other	2,960	3,394	(1,683)
Net cash used in investing activities	(127,457)	(320,456)	(227,243)
Cash flows from financing activities:
(Payments) draws on floor plan notes payable – non-trade, net	(369,592)	(104)	167,812
Proceeds from long-term debt	157,255	210,043	156,751
Principal payments on long-term debt	(255,279)	(183,538)	(167,106)
Principal payments on finance lease obligations	(11,192)	(8,331)	(12,429)
Draws on line of credit	0	135,000	0
Payments on line of credit	0	(135,000)	0
Proceeds from issuance of shares relating to employee stock options and employee stock purchases	21,037	8,244	3,926
Payments of cash dividends	(22,461)	(18,317)	(9,332)
Common stock repurchased	(24,865)	(58,188)	(120,558)
Debt issuance costs	0	(731)	0
Net cash (used in) provided by financing activities	(505,097)	(50,922)	19,064
Net increase (decrease) in cash and cash equivalents	130,428	49,894	7,185
Cash and cash equivalents, beginning of year	181,620	131,726	124,541
Cash and cash equivalents, end of year	312,048	181,620	131,726
Supplemental disclosure of cash flow information:
Interest	38,806	57,373	42,752
Income taxes paid, net	36,364	42,440	28,674
Assets acquired under finance leases	$ 49,523	44,904	$ 4,914
Guaranty agreement		$ 5,025