Segment Disclosures - Profit (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	$ 84,133	$ 68,942	$ 179,046	$ 157,131
Mortgage Banking	10,646	5,036	27,267	18,818
Equity-based compensation expense	(16,963)	(16,261)	(50,136)	(47,966)
Homebuilding Mid Atlantic [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	56,763	42,389	130,428	113,592
Homebuilding North East [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	8,383	3,981	16,476	11,780
Homebuilding Mid East [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	13,652	9,716	24,256	20,045
Homebuilding South East [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	5,555	2,851	13,839	10,315
Reportable segment [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	94,999	63,973	212,266	174,550
Contract land deposit reserve adjustment [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	(764)	133	586	(2,372)
Corporate capital allocation [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	24,712	19,182	66,239	52,502
Unallocated corporate overhead [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	(19,027)	(4,355)	(53,039)	(35,216)
Consolidation adjustments and other [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	2,486	6,365	4,562	15,938
Corporate interest expense [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	(1,310)	(95)	(1,432)	(305)
Reconciling items sub-total [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	$ (10,866)	$ 4,969	$ (33,220)	$ (17,419)