Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net income	$ 19,179	$ 33,328
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	44,228	34,267
Gain on sale of property and equipment	(29)	(87)
Stock-based compensation expense related to stock options and employee stock purchases	5,515	4,801
Provision for deferred income tax	(924)	5,785
Excess tax benefits from stock-based compensation	(2,138)	(1,428)
Change in accounts receivable, net	404	2,285
Change in inventories	(44,330)	(167,630)
Change in prepaid expenses and other, net	5,209	7,327
Change in trade accounts payable	19,552	13,314
Change in accrued expenses	(14,725)	(35,201)
Draws on floor plan notes payable – trade, net	4,789	36,067
Net cash provided by (used in) operating activities	36,730	(67,172)
Cash flows from investing activities:
Acquisition of property and equipment	(82,532)	(78,516)
Proceeds from the sale of property and equipment	332	1,042
Business acquisitions	(3,528)	(36)
Change in other assets	(66)	(644)
Net cash used in investing activities	(85,794)	(78,154)
Cash flows from financing activities:
Draws on floor plan notes payable – non-trade, net	33,002	77,889
Proceeds from long-term debt	65,651	63,914
Principal payments on long-term debt	(45,585)	(34,962)
Principal payments on capital lease obligations	(6,446)	(5,610)
Excess tax benefits from stock-based compensation	2,138	1,428
Proceeds from issuance of shares relating to employee stock options and employee stock purchases	7,337	3,897
Common stock repurchased	(2,272)
Net cash provided by financing activities	53,825	106,556
Net increase (decrease) in cash and cash equivalents	4,761	(38,770)
Cash and cash equivalents, beginning of period	198,773	207,775
Cash and cash equivalents, end of period	203,534	169,005
Supplemental disclosure of cash flow information:
Interest	11,334	11,409
Income taxes, net of refunds	1,360	2,598
Noncash investing activities:
Assets acquired under capital leases	$ 4,124	$ 4,624