Segment Information, Nature of Operations, and Certain Concentrations - Corporate Capital Allocation Charge (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Corporate Reconciling Items And Eliminations [Member]
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ (213,903)	$ (198,384)	$ (189,992)
Corporate Reconciling Items And Eliminations [Member] | Homebuilding: | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	(123,855)	(123,028)	(119,758)
Corporate Reconciling Items And Eliminations [Member] | Homebuilding: | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	(17,893)	(16,115)	(18,132)
Corporate Reconciling Items And Eliminations [Member] | Homebuilding: | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	(35,803)	(29,663)	(28,303)
Corporate Reconciling Items And Eliminations [Member] | Homebuilding: | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	(36,352)	(29,578)	(23,799)
Reconciling items:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Corporate capital allocation charge	$ 213,903	$ 198,384	$ 189,992