Debt and Credit Facilities (Details) (USD $)	12 Months Ended											12 Months Ended			12 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Senior notes	Dec. 31, 2010 Senior notes	Dec. 31, 2012 6.9 percent senior notes due June 2013	Dec. 31, 2011 6.9 percent senior notes due June 2013	Dec. 31, 2012 5.4 percent senior notes due January 2015	Dec. 31, 2011 5.4 percent senior notes due January 2015	Dec. 31, 2012 8.4 percent senior notes due May 2017	Dec. 31, 2011 8.4 percent senior notes due May 2017	Dec. 31, 2012 1.6 percent convertible senior notes due May 2018	May 10, 2012 1.6 percent convertible senior notes due May 2018	Dec. 31, 2011 1.6 percent convertible senior notes due May 2018	Dec. 31, 2010 6.6 percent senior notes due May 2020	Dec. 31, 2012 6.6 percent senior notes due May 2020	Dec. 31, 2011 6.6 percent senior notes due May 2020	Dec. 31, 2012 5.4 percent senior notes due October 2022	Dec. 31, 2011 5.4 percent senior notes due October 2022	Dec. 31, 2012 Seller-financed nonrecourse notes	Dec. 31, 2011 Seller-financed nonrecourse notes	Dec. 31, 2012 Repurchase credit facility JPMorgan Chase Bank, N.A. ("JPM")	Dec. 31, 2011 Repurchase credit facility JPMorgan Chase Bank, N.A. ("JPM")
Debt
Total senior notes	$ 1,131,481,000	$ 823,663,000				$ 0	$ 167,182,000	$ 126,481,000	$ 126,481,000	$ 230,000,000	$ 230,000,000	$ 225,000,000		$ 0		$ 300,000,000	$ 300,000,000	$ 250,000,000	$ 0
Debt discount	(3,000,000)	(3,647,000)
Senior notes, net	1,128,481,000	820,016,000
Secured notes payable	5,987,000	3,811,000																		5,987,000	3,811,000
Total debt	1,134,468,000	823,827,000
Financial services credit facility	0	49,933,000																				0	49,900,000
Maturities of debt
2013	4,054,000
2014	300,000
2015	126,494,000
2016	1,620,000
2017	230,000,000
After 2017	775,000,000
Total homebuilder debt and financial services credit facility	1,137,468,000
Other debt disclosures
Interest rate stated percentage						6.90%		5.40%		8.40%		1.60%				6.60%		5.40%
Net proceeds from senior notes	475,000,000	0	300,000,000															246,600,000
Principal amount of senior notes issued												225,000,000			300,000,000			250,000,000
Conversion ratio of debt instrument per $1,000 principal amount												0.0312
Debt instrument, initial conversion price (in dollars per share)												$ 32.03
Debt instrument, conversion premium (as a percent)												42.50%
Closing price of common stock (in dollars per share)													$ 22.48
Net proceeds from offering												218,800,000
Face value of additional debt instrument redeemed					255,700,000
Cash paid for redemption and repurchase of additional senior notes					273,900,000
Charges resulting from the tender offer and redemption					19,500,000
Face value of debt instrument redeemed and repurchased				51,500,000	27,000,000	177,200,000
Cash paid for redemption and repurchase of senior notes	177,219,000	52,917,000	300,554,000	52,900,000	26,600,000	167,200,000
(Loss) gain on repurchase of debt	(9,146,000)	(1,608,000)	(19,308,000)	(1,600,000)	196,000	(9,100,000)
Letters of credit outstanding	79,500,000	66,000,000
Maximum borrowing capacity																						$ 75,000,000	$ 50,000,000