Segment Information, Nature of Operations, and Certain Concentrations - Depreciation and Amortization (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 depreciation and amortization	$ 20,818	$ 20,168	$ 22,667
Profit before taxes:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	17,495	16,846	17,547
Profit before taxes: | Homebuilding: | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	7,069	7,753	8,095
Profit before taxes: | Homebuilding: | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	1,411	1,600	2,034
Profit before taxes: | Homebuilding: | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	4,348	3,481	3,590
Profit before taxes: | Homebuilding: | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	3,086	2,523	2,531
Profit before taxes: | Mortgage Banking:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	1,581	1,489	1,297
Other unallocated interest income
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	$ 3,323	$ 3,322	$ 5,120