Segment Disclosures - Corporate Capital Allocation Charge (Detail) - Corporate and Reconciling Items - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 64,055	$ 60,662	$ 188,638	$ 177,184
Home Building Segment | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	31,057	31,383	92,788	92,720
Home Building Segment | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	6,719	5,793	19,214	17,142
Home Building Segment | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	11,114	10,386	32,804	29,436
Home Building Segment | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 15,165	$ 13,100	$ 43,832	$ 37,886