Segment Disclosures - Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 4,730,020	$ 3,809,815
Contract land deposit reserve	(63,647)	(27,572)
Home Building [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	4,338,097	3,242,061
Cash and cash equivalents	1,982,890	1,110,892
Operating lease right-of-use assets	57,701	63,825
Mortgage Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	391,923	567,754
Cash and cash equivalents	17,986	29,412
Operating lease right-of-use assets	14,226	13,345
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,513,165	2,447,015
Operating Segments [Member] | Home Building [Member] | Mid Atlantic [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,148,688	1,024,996
Operating Segments [Member] | Home Building [Member] | North East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	189,076	166,860
Operating Segments [Member] | Home Building [Member] | Mid East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	346,232	293,773
Operating Segments [Member] | Home Building [Member] | South East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	444,593	400,979
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	384,576	560,407
Corporate and Reconciling Items [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,216,855	1,362,800
Cash and cash equivalents	1,982,890	1,110,892
Deferred taxes	121,526	115,731
Intangible assets and goodwill	49,756	49,834
Operating lease right-of-use assets	57,701	63,825
Contract land deposit reserve	(63,647)	(27,572)
Consolidation adjustments and other	$ 68,629	$ 50,090