Segment Information, Nature of Operations, and Certain Concentrations - Corporate Capital Allocation Charge (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Corporate Reconciling Items And Eliminations [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ (239,233)	$ (224,468)	$ (213,903)
Corporate Reconciling Items And Eliminations [Member] | Home Building | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	(124,426)	(123,130)	(123,855)
Corporate Reconciling Items And Eliminations [Member] | Home Building | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	(22,850)	(19,755)	(17,893)
Corporate Reconciling Items And Eliminations [Member] | Home Building | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	(40,256)	(37,263)	(35,803)
Corporate Reconciling Items And Eliminations [Member] | Home Building | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	(51,701)	(44,320)	(36,352)
Reconciling items:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ (239,233)	$ (224,468)	$ (213,903)