Segment Disclosures - Corporate Capital Allocation Charge (Detail) - Corporate and Reconciling Items - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 61,551	$ 56,650
Home Building Segment | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	30,596	29,755
Home Building Segment | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	6,038	5,558
Home Building Segment | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	10,624	9,363
Home Building Segment | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 14,293	$ 11,974