Supplemental Guarantor Information (Statement Of Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net cash provided by (used in) operating activities	$ 1,449,744	$ 663,077	$ 68,270
Cash flows from investing activities:
Capital expenditures	(59,039)	(32,051)	(39,295)
Investment in unconsolidated subsidiaries	(1,000)	(23,037)	(14,539)
Cash used for business acquisition	0	0	(430,458)
Other investing activities, net	18,097	4,846	13,100
Net cash used in investing activities	(41,942)	(50,242)	(471,192)
Cash flows from financing activities:
Proceeds from debt, net of issuance costs		0	1,995,937
Payments of Debt Issuance Costs	(8,164)
Financial Services borrowings (repayments), net	(89,393)	106,183	63,744
Repayments of debt	(82,775)	(134,747)	(986,919)
Borrowings under revolving credit facility	1,566,000	2,720,000	619,000
Repayments under revolving credit facility	(1,566,000)	(2,720,000)	(619,000)
Stock option exercises	6,555	27,720	5,845
Share repurchases	(302,473)	(916,323)	(603,206)
Dividends paid	(104,020)	(112,748)	(124,666)
Intercompany activities, net	0	0	0
Net cash provided by (used in) financing activities	(580,270)	(1,029,915)	350,735
Net increase (decrease)	827,532	(417,080)	(52,187)
Cash, cash equivalents, and restricted cash at beginning of period	306,168	723,248	775,435
Cash, cash equivalents, and restricted cash at end of period	1,133,700	306,168	723,248
Parent Company [Member]
Net cash provided by (used in) operating activities	494,518	309,757	256,722
Cash flows from investing activities:
Capital expenditures	0	0	0
Investment in unconsolidated subsidiaries	0	0	0
Cash used for business acquisition			0
Other investing activities, net	0	0	0
Net cash used in investing activities	0	0	0
Cash flows from financing activities:
Proceeds from debt, net of issuance costs		0	1,991,937
Payments of Debt Issuance Costs	(8,164)
Financial Services borrowings (repayments), net	0	0	0
Repayments of debt	0	(123,000)	(965,245)
Borrowings under revolving credit facility	1,566,000	2,720,000	619,000
Repayments under revolving credit facility	(1,566,000)	(2,720,000)	(619,000)
Stock option exercises	6,555	27,720	5,845
Share repurchases	(302,473)	(916,323)	(603,206)
Dividends paid	(104,020)	(112,748)	(124,666)
Intercompany activities, net	(86,416)	814,594	(561,387)
Net cash provided by (used in) financing activities	(494,518)	(309,757)	(256,722)
Net increase (decrease)	0	0	0
Cash, cash equivalents, and restricted cash at beginning of period	0	0	0
Cash, cash equivalents, and restricted cash at end of period	0	0	0
Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	791,350	328,163	(102,054)
Cash flows from investing activities:
Capital expenditures	(51,147)	(25,432)	(36,297)
Investment in unconsolidated subsidiaries	(1,000)	(23,037)	(14,539)
Cash used for business acquisition			(430,458)
Other investing activities, net	11,300	5,778	11,189
Net cash used in investing activities	(40,847)	(42,691)	(470,105)
Cash flows from financing activities:
Proceeds from debt, net of issuance costs		0	4,000
Payments of Debt Issuance Costs	0
Financial Services borrowings (repayments), net	0	0	0
Repayments of debt	(81,758)	(10,301)	(21,235)
Borrowings under revolving credit facility	0	0	0
Repayments under revolving credit facility	0	0	0
Stock option exercises	0	0	0
Share repurchases	0	0	0
Dividends paid	0	0	0
Intercompany activities, net	102,821	(728,555)	541,703
Net cash provided by (used in) financing activities	21,063	(738,856)	524,468
Net increase (decrease)	771,566	(453,384)	(47,691)
Cash, cash equivalents, and restricted cash at beginning of period	157,801	611,185	658,876
Cash, cash equivalents, and restricted cash at end of period	929,367	157,801	611,185
Non-Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	163,876	25,157	(86,398)
Cash flows from investing activities:
Capital expenditures	(7,892)	(6,619)	(2,998)
Investment in unconsolidated subsidiaries	0	0	0
Cash used for business acquisition			0
Other investing activities, net	6,797	(932)	1,911
Net cash used in investing activities	(1,095)	(7,551)	(1,087)
Cash flows from financing activities:
Proceeds from debt, net of issuance costs		0	0
Payments of Debt Issuance Costs	0
Financial Services borrowings (repayments), net	(89,393)	106,183	63,744
Repayments of debt	(1,017)	(1,446)	(439)
Borrowings under revolving credit facility	0	0	0
Repayments under revolving credit facility	0	0	0
Stock option exercises	0	0	0
Share repurchases	0	0	0
Dividends paid	0	0	0
Intercompany activities, net	(16,405)	(86,039)	19,684
Net cash provided by (used in) financing activities	(106,815)	18,698	82,989
Net increase (decrease)	55,966	36,304	(4,496)
Cash, cash equivalents, and restricted cash at beginning of period	148,367	112,063	116,559
Cash, cash equivalents, and restricted cash at end of period	204,333	148,367	112,063
Eliminating Entries [Member]
Net cash provided by (used in) operating activities	0	0	0
Cash flows from investing activities:
Capital expenditures	0	0	0
Investment in unconsolidated subsidiaries	0	0	0
Cash used for business acquisition			0
Other investing activities, net	0	0	0
Net cash used in investing activities	0	0	0
Cash flows from financing activities:
Proceeds from debt, net of issuance costs		0	0
Payments of Debt Issuance Costs	0
Financial Services borrowings (repayments), net	0	0	0
Repayments of debt	0	0	0
Borrowings under revolving credit facility	0	0	0
Repayments under revolving credit facility	0	0	0
Stock option exercises	0	0	0
Share repurchases	0	0	0
Dividends paid	0	0	0
Intercompany activities, net	0	0	0
Net cash provided by (used in) financing activities	0	0	0
Net increase (decrease)	0	0	0
Cash, cash equivalents, and restricted cash at beginning of period	0	0	0
Cash, cash equivalents, and restricted cash at end of period	$ 0	$ 0	$ 0