Segment Disclosures - Corporate Capital Allocation Charge (Detail) - Reconciling Items [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 45,690	$ 42,220	$ 124,033	$ 105,697
Homebuilding [Member] | Mid Atlantic [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	28,743	27,187	78,412	67,085
Homebuilding [Member] | North East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	4,451	3,151	11,566	8,333
Homebuilding [Member] | Mid East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	7,472	7,202	20,079	18,680
Homebuilding [Member] | South East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 5,024	$ 4,680	$ 13,976	$ 11,599