Segment Disclosures - Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 3,603,240		$ 3,165,933
Operating Lease, Right-of-Use Asset		$ 79,345
Contract land deposit reserve	(27,892)		(29,216)
Home Building [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	3,058,397		2,641,511
Cash and cash equivalents	860,956		688,783
Operating Lease, Right-of-Use Asset	65,027		0
Mortgage Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	544,843		524,422
Cash and cash equivalents	21,363		23,092
Operating Lease, Right-of-Use Asset	14,078		0
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,485,230		2,303,723
Operating Segments [Member] | Home Building [Member] | Mid Atlantic [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,082,646		1,018,953
Operating Segments [Member] | Home Building [Member] | North East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	154,143		144,412
Operating Segments [Member] | Home Building [Member] | Mid East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	330,446		290,815
Operating Segments [Member] | Home Building [Member] | South East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	380,499		332,468
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	537,496		517,075
Corporate and Reconciling Items [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,118,010		862,210
Cash and cash equivalents	860,956		688,783
Deferred taxes	115,432		112,333
Intangible assets and goodwill	49,911		49,989
Operating Lease, Right-of-Use Asset	65,027		0
Contract land deposit reserve	(27,892)		(29,216)
Consolidation adjustments and other	$ 54,576		$ 40,321