Quarterly Results - Quarterly Financial Data and Operating Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012 Contract Settlements Backlog	Sep. 30, 2012 Settlements Backlog Contract	Jun. 30, 2012 Backlog Contract Settlements	Mar. 31, 2012 Contract Settlements Backlog	Dec. 31, 2011 Backlog Contract Settlements	Sep. 30, 2011 Backlog Settlements Contract	Jun. 30, 2011 Backlog Contract Settlements	Mar. 31, 2011 Backlog Settlements Contract	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Data [Line Items]
Mortgage banking fees									$ 63,406	$ 47,954	$ 61,134
Net income	60,627	53,000	46,838	20,123	32,392	43,409	38,445	15,174	180,588	129,420	206,005
Diluted earnings per share	$ 11.98	$ 10.33	$ 8.97	$ 3.90	$ 6.32	$ 7.98	$ 6.48	$ 2.52	$ 35.12	$ 23.01	$ 33.42
Contracts for sale, net of cancellations (units)	2,625	2,558	2,614	3,157	2,158	2,218	2,468	2,403
Settlements (units)	2,788	2,656	2,475	1,924	2,391	2,255	2,207	1,634
Backlog, end of period (units)	4,979	4,950	5,048	4,909	3,676	3,909	3,946	3,685
Loans closed	642,171	594,867	548,871	420,184	520,919	489,866	504,116	353,571
Homebuilding [Member]
Quarterly Financial Data [Line Items]
Revenues	925,363	854,396	755,290	586,195	728,808	696,980	682,663	502,744	3,121,244	2,611,195	2,980,758
Gross profit - homebuilding operations	168,967	151,960	130,312	94,366	112,086	124,598	124,062	84,824
Mortgage Banking [Member]
Quarterly Financial Data [Line Items]
Mortgage banking fees	$ 18,375	$ 16,241	$ 14,493	$ 14,297	$ 12,480	$ 10,496	$ 13,218	$ 11,760	$ 63,406	$ 47,954	$ 61,134