Segment Information, Nature of Operations, and Certain Concentrations - Corporate Capital Allocation Charge (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Corporate Reconciling Items And Eliminations [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation (2)	$ (224,468)	$ (213,903)	$ (198,384)
Corporate Reconciling Items And Eliminations [Member] | Homebuilding: | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation (2)	(123,130)	(123,855)	(123,028)
Corporate Reconciling Items And Eliminations [Member] | Homebuilding: | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation (2)	(19,755)	(17,893)	(16,115)
Corporate Reconciling Items And Eliminations [Member] | Homebuilding: | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation (2)	(37,263)	(35,803)	(29,663)
Corporate Reconciling Items And Eliminations [Member] | Homebuilding: | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation (2)	(44,320)	(36,352)	(29,578)
Reconciling items:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation (2)	$ 224,468	$ 213,903	$ 198,384