Segment Disclosures - Profit (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	$ 143,791	$ 131,590	$ 302,322	$ 266,876
Corporate Capital Allocation [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	42,220	31,297	105,697	86,588
Homebuilding Mid Atlantic [Member] | Corporate Capital Allocation [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	27,187	19,320	67,085	54,036
Homebuilding North East [Member] | Corporate Capital Allocation [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	3,151	2,487	8,333	6,834
Homebuilding Mid East [Member] | Corporate Capital Allocation [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	7,202	6,137	18,680	16,868
Homebuilding South East [Member] | Corporate Capital Allocation [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	4,680	3,353	11,599	8,850
Operating Segments [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	122,682	146,544	281,820	282,994
Operating Segments [Member] | Homebuilding Mid Atlantic [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	76,542	92,496	184,900	177,762
Operating Segments [Member] | Homebuilding North East [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	9,056	8,031	23,761	18,114
Operating Segments [Member] | Homebuilding Mid East [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	18,374	21,823	29,241	33,058
Operating Segments [Member] | Homebuilding South East [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	10,093	11,529	26,034	20,277
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Consolidated income before taxes	8,617	12,665	17,884	33,783
Reconciling Items Sub-Total [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	21,109	(14,954)	20,502	(16,118)
Reconciling Items Sub-Total [Member] | Contract Land Deposit Reserve Adjustment [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	453	699	4,108	4,551
Reconciling Items Sub-Total [Member] | Equity-Based Compensation Expense [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	(18,233)	(11,733)	(44,874)	(30,385)
Reconciling Items Sub-Total [Member] | Corporate Capital Allocation [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	42,220	31,297	105,697	86,588
Reconciling Items Sub-Total [Member] | Unallocated Corporate Overhead [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	(8,179)	(13,969)	(49,652)	(60,139)
Reconciling Items Sub-Total [Member] | Corporate Interest Expense [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	(5,616)	(5,505)	(16,870)	(16,128)
Consolidation adjustments and other [Member]
Segment Reporting, Profit Reconciling Item [Line Items]
Segment reporting reconciling item for operating profit	$ 10,464	$ (15,743)	$ 22,093	$ (605)