Segment Disclosures - Corporate Capital Allocation Charge (Detail) - Corporate and Reconciling Items [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 49,646	$ 46,259	$ 95,833	$ 90,574
Homebuilding [Member] | Mid Atlantic [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	31,005	28,766	60,130	55,951
Homebuilding [Member] | North East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	4,133	4,447	7,947	9,400
Homebuilding [Member] | Mid East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	7,535	7,458	14,277	14,157
Homebuilding [Member] | South East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 6,973	$ 5,588	$ 13,479	$ 11,066