Supplemental Guarantor Information (Statement Of Cash Flows) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net cash provided by (used in) operating activities	$ 309,249,000	$ 881,136,000	$ 760,140,000
Cash flows from investing activities:
Distributions from unconsolidated entities	8,157,000	1,001,000	3,029,000
Investments in unconsolidated entities	(9,000)	(1,677,000)	(16,456,000)
Net change in loans held for investment	335,000	(12,265,000)	836,000
Change in restricted cash related to letters of credit	54,989,000	(4,152,000)	28,653,000
Proceeds from the sale of property and equipment	113,000	15,000	7,586,000
Capital expenditures	(48,790,000)	(28,899,000)	(13,942,000)
Cash used for business acquisition	(82,419,000)	0	0
Net cash provided by (used in) investing activities	(67,624,000)	(45,977,000)	9,706,000
Cash flows from financing activities:
Financial Services borrowings (repayments)	34,577,000	(33,131,000)	138,795,000
Other borrowings (repayments)	(250,631,000)	(479,827,000)	(618,800,000)
Stock option exercises	15,627,000	19,411,000	32,809,000
Stock repurchases	(253,019,000)	(127,661,000)	(961,000)
Dividends paid	(75,646,000)	(38,382,000)	0
Intercompany activities, net	0	0	0
Net cash used in financing activities	(529,092,000)	(659,590,000)	(448,157,000)
Net increase (decrease) in cash and equivalents	(287,467,000)	175,569,000	321,689,000
Cash and equivalents at beginning of period	1,580,329,000	1,404,760,000	1,083,071,000
Cash and equivalents at end of period	1,292,862,000	1,580,329,000	1,404,760,000
Parent Company [Member]
Net cash provided by (used in) operating activities	206,485,000	(41,000)	(582,762,000)
Cash flows from investing activities:
Distributions from unconsolidated entities	0	0	0
Investments in unconsolidated entities	0	0	0
Net change in loans held for investment	0	0	0
Change in restricted cash related to letters of credit	54,989,000	(4,152,000)	28,653,000
Proceeds from the sale of property and equipment	0	0	0
Capital expenditures	0	0	0
Cash used for business acquisition	0
Net cash provided by (used in) investing activities	54,989,000	(4,152,000)	28,653,000
Cash flows from financing activities:
Financial Services borrowings (repayments)	0	0	0
Other borrowings (repayments)	(249,765,000)	(485,048,000)	(620,700,000)
Stock option exercises	15,627,000	19,411,000	32,809,000
Stock repurchases	(253,019,000)	(127,661,000)	(961,000)
Dividends paid	(75,646,000)	(38,382,000)
Intercompany activities, net	46,419,000	752,069,000	1,169,842,000
Net cash used in financing activities	(516,384,000)	120,389,000	580,990,000
Net increase (decrease) in cash and equivalents	(254,910,000)	116,196,000	26,881,000
Cash and equivalents at beginning of period	262,364,000	146,168,000	119,287,000
Cash and equivalents at end of period	7,454,000	262,364,000	146,168,000
Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	175,415,000	865,267,000	1,332,342,000
Cash flows from investing activities:
Distributions from unconsolidated entities	8,161,000	1,001,000	3,029,000
Investments in unconsolidated entities	0	(1,677,000)	(16,456,000)
Net change in loans held for investment	0	0	0
Change in restricted cash related to letters of credit	0	0	0
Proceeds from the sale of property and equipment	113,000	15,000	7,586,000
Capital expenditures	(44,956,000)	(26,472,000)	(10,831,000)
Cash used for business acquisition	(82,419,000)
Net cash provided by (used in) investing activities	(119,101,000)	(27,133,000)	(16,672,000)
Cash flows from financing activities:
Financial Services borrowings (repayments)	0	0	0
Other borrowings (repayments)	(866,000)	5,221,000	1,900,000
Stock option exercises	0	0	0
Stock repurchases	0	0	0
Dividends paid	0	0
Intercompany activities, net	(87,140,000)	(718,299,000)	(1,129,188,000)
Net cash used in financing activities	(88,006,000)	(713,078,000)	(1,127,288,000)
Net increase (decrease) in cash and equivalents	(31,692,000)	125,056,000	188,382,000
Cash and equivalents at beginning of period	1,188,999,000	1,063,943,000	875,561,000
Cash and equivalents at end of period	1,157,307,000	1,188,999,000	1,063,943,000
Non-Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	(72,651,000)	15,910,000	10,560,000
Cash flows from investing activities:
Distributions from unconsolidated entities	(4,000)	0	0
Investments in unconsolidated entities	(9,000)	0	0
Net change in loans held for investment	335,000	(12,265,000)	836,000
Change in restricted cash related to letters of credit	0	0	0
Proceeds from the sale of property and equipment	0	0	0
Capital expenditures	(3,834,000)	(2,427,000)	(3,111,000)
Cash used for business acquisition	0
Net cash provided by (used in) investing activities	(3,512,000)	(14,692,000)	(2,275,000)
Cash flows from financing activities:
Financial Services borrowings (repayments)	34,577,000	(33,131,000)	138,795,000
Other borrowings (repayments)	0		0
Stock option exercises	0	0	0
Stock repurchases	0	0	0
Dividends paid	0	0
Intercompany activities, net	40,721,000	(33,770,000)	(40,654,000)
Net cash used in financing activities	75,298,000	(66,901,000)	98,141,000
Net increase (decrease) in cash and equivalents	(865,000)	(65,683,000)	106,426,000
Cash and equivalents at beginning of period	128,966,000	194,649,000	88,223,000
Cash and equivalents at end of period	128,101,000	128,966,000	194,649,000
Eliminating Entries [Member]
Net cash provided by (used in) operating activities	0	0	0
Cash flows from investing activities:
Distributions from unconsolidated entities	0	0	0
Investments in unconsolidated entities	0	0	0
Net change in loans held for investment	0	0	0
Change in restricted cash related to letters of credit	0	0	0
Proceeds from the sale of property and equipment	0	0	0
Capital expenditures	0	0	0
Cash used for business acquisition	0
Net cash provided by (used in) investing activities	0	0	0
Cash flows from financing activities:
Financial Services borrowings (repayments)	0		0
Other borrowings (repayments)	0		0
Stock option exercises	0	0	0
Stock repurchases	0	0	0
Dividends paid	0	0
Intercompany activities, net	0	0	0
Net cash used in financing activities	0	0	0
Net increase (decrease) in cash and equivalents	0	0	0
Cash and equivalents at beginning of period	0	0	0
Cash and equivalents at end of period	$ 0	$ 0	$ 0