Segment Disclosures - Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 5,788,894	$ 5,777,141
Finance Lease, Right-of-Use Asset	14,706	15,772
Contract land deposit reserve	(34,704)	(52,205)
Home Building Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	5,431,230	5,214,516
Cash and cash equivalents	2,681,110	2,714,720
Operating lease right-of-use assets	60,605	53,110
Mortgage Banking
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	357,664	562,625
Cash and cash equivalents	21,999	63,547
Operating lease right-of-use assets	10,747	12,439
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,778,705	2,770,522
Operating Segments | Home Building Segment | Mid Atlantic
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,183,206	1,140,910
Operating Segments | Home Building Segment | North East
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	230,813	202,591
Operating Segments | Home Building Segment | Mid East
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	432,723	377,448
Operating Segments | Home Building Segment | South East
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	581,646	494,295
Operating Segments | Mortgage Banking
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	350,317	555,278
Corporate and Reconciling Items
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	3,010,189	3,006,619
Cash and cash equivalents	2,681,110	2,714,720
Deferred taxes	136,446	132,980
Intangible assets and goodwill	49,562	49,678
Operating lease right-of-use assets	60,605	53,110
Finance Lease, Right-of-Use Asset	14,706	15,772
Contract land deposit reserve	(34,704)	(52,205)
Consolidation adjustments and other	$ 102,464	$ 92,564