Segment Information, Nature of Operations, and Certain Concentrations - Interest Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	$ 25,380	$ 25,081	$ 24,185
Homebuilding:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	24,335	24,036	23,037
Mortgage Banking:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	1,045	1,045	1,148
Profit before taxes:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	225,627	215,016	199,586
Profit before taxes: | Homebuilding: | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	123,178	123,908	123,075
Profit before taxes: | Homebuilding: | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	19,804	17,897	16,117
Profit before taxes: | Homebuilding: | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	37,266	35,804	29,663
Profit before taxes: | Homebuilding: | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	44,334	36,362	29,583
Profit before taxes: | Mortgage Banking:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	1,045	1,045	1,148
Reconciling items:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	$ 24,221	$ 23,968	$ 22,983