Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 139,062	$ 172,129	$ 40,582
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	185,122	157,951	157,627
(Gain) loss on sale of property and equipment, net	(297)	105	(1,755)
Loss on impairment of assets			8,247
Stock-based compensation expense related to employee stock options and employee stock purchases	18,059	15,606	12,875
Provision (benefit) for deferred income tax expense	5,997	(62,203)	8,331
Excess tax expense from stock-based compensation			294
Change in accounts receivable, net	(7,746)	(29,424)	1,673
Change in inventories	(255,040)	(147,453)	291,773
Change in prepaid expenses and other, net	1,907	(3,383)	24,155
Change in trade accounts payable	18,490	8,964	(22,411)
Draws on floor plan notes payable – trade, net	76,646	19,355	3,989
Change in customer deposits	8,833	8,932	(4,020)
Change in accrued expenses	24,331	12,158	(190)
Net cash provided by operating activities	215,364	152,737	521,170
Cash flows from investing activities:
Acquisition of property and equipment	(238,260)	(209,917)	(196,965)
Proceeds from the sale of property and equipment	6,325	3,968	12,494
Business acquisitions		(2,180)	(681)
Proceeds from the sale of available for sale securities	6,375	325	450
Other	(1,683)	1,241	(4,708)
Net cash used in investing activities	(227,243)	(206,563)	(189,410)
Cash flows from financing activities:
Draws (payments) on floor plan notes payable – non-trade, net	167,812	112,261	(211,802)
Proceeds from long-term debt	156,751	152,563	121,188
Principal payments on long-term debt	(167,106)	(145,038)	(164,940)
Principal payments on capital lease obligations	(12,429)	(12,449)	(23,479)
Proceeds from issuance of shares relating to employee stock options and employee stock purchases	3,926	23,327	8,260
Excess tax expense from stock-based compensation			(294)
Common stock repurchased	(120,558)	(33,800)	(43,514)
Payments of cash dividends	(9,332)
Debt issuance costs		(523)
Net cash provided by (used in) financing activities	19,064	96,341	(314,581)
Net increase (decrease) in cash and cash equivalents	7,185	42,515	17,179
Cash and cash equivalents, beginning of year	124,541	82,026	64,847
Cash and cash equivalents, end of year	131,726	124,541	82,026
Supplemental disclosure of cash flow information:
Interest	42,752	34,149	37,904
Income taxes paid (refunded), net	28,674	31,323	(10,939)
Noncash investing and financing activities:
Assets acquired under capital leases	$ 4,914	$ 15,205	$ 24,207