Segment Disclosures - Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 3,362,771		$ 3,165,933
Operating Lease, Right-of-Use Asset		$ 79
Contract land deposit reserve	(28,266)		(29,216)
Home Building [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,868,276		2,641,511
Cash and cash equivalents	805,195		688,783
Operating Lease, Right-of-Use Asset	65,519		0
Mortgage Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	494,495		524,422
Cash and cash equivalents	11,258		23,092
Operating Lease, Right-of-Use Asset	12,370		0
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,304,270		2,303,723
Operating Segments [Member] | Home Building [Member] | Mid Atlantic [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,043,004		1,018,953
Operating Segments [Member] | Home Building [Member] | North East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	146,750		144,412
Operating Segments [Member] | Home Building [Member] | Mid East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	294,293		290,815
Operating Segments [Member] | Home Building [Member] | South East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	333,075		332,468
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	487,148		517,075
Corporate and Reconciling Items [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,058,501		862,210
Cash and cash equivalents	805,195		688,783
Deferred taxes	115,160		112,333
Intangible assets and goodwill	49,950		49,989
Operating Lease, Right-of-Use Asset	65,519		0
Contract land deposit reserve	(28,266)		(29,216)
Consolidation adjustments and other	$ 50,943		$ 40,321