Segment Disclosures - Corporate Capital Allocation Charge (Detail) - Corporate and Reconciling Items [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 57,887	$ 55,438	$ 168,621	$ 160,091
Home Building [Member] | Mid Atlantic [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	31,504	31,733	93,297	93,682
Home Building [Member] | North East [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	5,028	4,565	14,381	13,325
Home Building [Member] | Mid East [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	9,791	9,541	28,303	26,571
Home Building [Member] | South East [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 11,564	$ 9,599	$ 32,640	$ 26,513