Segment Information, Nature of Operations, and Certain Concentrations - Interest Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	$ 40,872	$ 25,380	$ 25,081
Home Building
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	39,458	24,335	24,036
Mortgage Banking
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	1,414	1,045	1,045
Profit before taxes:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	240,749	225,627	215,016
Profit before taxes: | Home Building | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	124,486	123,178	123,908
Profit before taxes: | Home Building | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	22,859	19,804	17,897
Profit before taxes: | Home Building | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	40,261	37,266	35,804
Profit before taxes: | Home Building | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	51,729	44,334	36,362
Profit before taxes: | Mortgage Banking
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	1,414	1,045	1,045
Reconciling items:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated interest expense	39,356	24,221	23,968
Corporate capital allocation charge	$ (239,233)	$ (224,468)	$ (213,903)