Segment Disclosures - Corporate Capital Allocation Charge (Detail) - Reconciling Items [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 50,032	$ 45,690	$ 140,606	$ 124,033
Homebuilding [Member] | Mid Atlantic [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	31,960	28,743	87,911	78,412
Homebuilding [Member] | North East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	4,572	4,451	13,972	11,566
Homebuilding [Member] | Mid East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	7,366	7,472	21,523	20,079
Homebuilding [Member] | South East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 6,134	$ 5,024	$ 17,200	$ 13,976