Segment Information, Nature of Operations, and Certain Concentrations - Depreciation and Amortization (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	$ 20,168	$ 22,667	$ 22,269
Profit before taxes:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	16,846	17,547	17,283
Profit before taxes: | Homebuilding: | Mid Atlantic
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	7,753	8,095	8,089
Profit before taxes: | Homebuilding: | North East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	1,600	2,034	2,053
Profit before taxes: | Homebuilding: | Mid East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	3,481	3,590	3,748
Profit before taxes: | Homebuilding: | South East
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	2,523	2,531	2,276
Profit before taxes: | Mortgage Banking:
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	1,489	1,297	1,117
Other unallocated interest income
Segment Reporting, Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	$ 3,322	$ 5,120	$ 4,986