Segment Disclosures - Corporate Capital Allocation Charge (Detail) - Corporate and Reconciling Items [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 59,870	$ 56,177	$ 116,521	$ 110,735
Home Building [Member] | Mid Atlantic [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	31,581	31,378	61,336	61,794
Home Building [Member] | North East [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	5,790	4,626	11,349	9,353
Home Building [Member] | Mid East [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	9,687	9,497	19,050	18,512
Home Building [Member] | South East [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 12,812	$ 10,676	$ 24,786	$ 21,076