Segment Information, Nature of Operations, and Certain Concentrations - Interest Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest expense	$ 23,140	$ 22,385	$ 7,529
Mortgage Banking [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest expense	549	545	546
Operating Segments [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest expense	152,736	117,100	92,240
Operating Segments [Member] | Homebuilding Mid Atlantic [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest expense	96,364	72,351	59,310
Operating Segments [Member] | Homebuilding North East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest expense	12,114	9,466	8,196
Operating Segments [Member] | Homebuilding Mid East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest expense	26,300	22,587	15,043
Operating Segments [Member] | Homebuilding South East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest expense	17,409	12,151	9,145
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest expense	549	545	546
Reconciling Items Sub-Total [Member] | Corporate Capital Allocation [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Segment reporting reconciling item	(152,140)	(116,457)	(91,507)
Consolidation adjustments and other [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Segment reporting reconciling item	(23,867)	(2,362)	(10,858)
Consolidation adjustments and other [Member] | Senior Notes And Other Interest [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Senior notes and other interest	$ 22,544	$ 21,742	$ 6,796