Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net borrowings on 5.25% Senior Unsecured Notes	$ 0	$ 0	$ 296,250
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	213,442	147,065	93,999
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	57,936	51,234	47,239
Deferred income taxes	46,063	(14,162)	(11,884)
Asset impairments	19,506	32,838	87,562
Stock-based compensation	18,900	21,073	18,851
Amortization of debt discount and issue costs	3,661	3,694	3,652
Gain on disposition of assets	(781)	2,675	9,719
Other	407	1,084	1,192
Changes in operating assets and liabilities, net of effects of acquisitions and dispositions:
Accounts payable and accrued expenses	35,576	76,126	25,108
Accounts and notes receivable	10,674	(18,663)	(17,887)
Inventories	44,021	79,319	(186,634)
Contracts-in-transit and vehicle receivables	33,484	(15,621)	(17,944)
Prepaid expenses and other assets	6,889	8,244	(3,153)
Floorplan notes payable — manufacturer affiliates	8,294	(12,630)	87,516
Deferred revenues	517	(393)	(619)
Net cash provided by (used in) operating activities	198,925	384,857	141,047
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash paid in acquisitions, net of cash received	(109,081)	(57,327)	(212,252)
Proceeds from disposition of franchises, property and equipment	10,708	36,843	41,581
Purchases of property and equipment, including real estate	(215,832)	(156,521)	(120,252)
Other	1,607	2,965	6,421
Net cash provided by (used in) investing activities	(312,598)	(174,040)	(284,502)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings on credit facility — floorplan line and other	7,019,070	6,597,406	7,557,237
Repayments on credit facility — floorplan line and other	(6,957,866)	(6,676,161)	(7,504,516)
Borrowings on credit facility — acquisition line	68,086	220,020	489,548
Repayments on credit facility — acquisition line	(42,278)	(220,020)	(557,696)
Debt issue costs		3,513	788
Borrowings on other debt	165,702	49,972	59,855
Principal payments on other debt	(121,199)	(45,928)	(63,769)
Borrowings on debt related to real estate, net of debt issue costs	(75,309)	(42,654)	(32,026)
Borrowings Of Long Term Debt Related To Real Estate Loans, Net of Debt Issue Costs		39,141	31,238
Principal payments on debt related to real estate	(29,391)	(25,463)	(72,079)
Net Issuance of Common and Treasury Shares to Employee Stock Compensation Plans	4,603	3,868	214
Repurchases of common stock, amounts based on settlement date	(40,094)	(127,606)	(97,473)
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	0	(249)	2,142
Dividends paid	(20,466)	(19,987)	(19,942)
Net cash provided by (used in) financing activities	121,476	(205,007)	121,009
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(8)	2,145	(5,492)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	7,795	7,955	(27,938)
CASH AND CASH EQUIVALENTS, beginning of period	20,992	13,037	40,975
CASH AND CASH EQUIVALENTS, end of period	28,787	20,992	13,037
SUPPLEMENTAL CASH FLOW INFORMATION:
Purchases of property and equipment, including real estate, accrued in accounts payable and accrued expenses	$ 8,759	$ 15,930	$ 32,720