Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 21,039	$ 14,479
Adjustments to reconcile net income to net cash provided by operating activities-
Depreciation and amortization	51,056	38,724
Loss on sale of property and equipment, net	28	163
Stock-based compensation expense related to employee stock options and employee stock purchases	7,893	4,759
Provision for deferred income tax expense	755	1,408
Change in accounts receivable, net	(7,140)	(12,901)
Change in inventories	5,706	(19,376)
Change in prepaid expenses and other, net	(2,103)	(609)
Change in trade accounts payable	12,912	1,690
Draws on floor plan notes payable – trade, net	35,380	18,552
Change in customer deposits	38	(2,201)
Change in accrued expenses	(7,900)	(7,163)
Net cash provided by operating activities	117,664	37,525
Cash flows from investing activities:
Acquisition of property and equipment	(48,215)	(39,209)
Proceeds from the sale of property and equipment	2,231	1,600
Other	(1,098)	5,160
Net cash used in investing activities	(47,082)	(32,449)
Cash flows from financing activities:
(Payments) draws on floor plan notes payable – non-trade, net	(8,410)	19,098
Proceeds from long-term debt	32,137	25,555
Principal payments on long-term debt	(46,278)	(38,113)
Principal payments on capital lease obligations	(3,224)	(3,337)
Issuance of shares relating to employee stock options and employee stock purchases	501	6,851
Common stock repurchased	(38,137)	(7,560)
Debt issuance costs		(523)
Net cash (used in) provided by financing activities	(63,411)	1,971
Net decrease in cash and cash equivalents	7,171	7,047
Cash and cash equivalents, beginning of period	124,541	82,026
Cash and cash equivalents, end of period	131,712	89,073
Supplemental disclosure of cash flow information:
Interest	9,943	8,211
Income taxes paid, net	1,500	6,201
Noncash investing and financing activities:
Assets acquired under capital leases	$ 401	$ 2,073