Segment Information, Nature of Operations, and Certain Concentrations - Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 3,809,815		$ 3,165,933
Operating lease right-of-use assets		$ 79,345
Contract land deposit reserve	(27,572)		(29,216)
Homebuilding:
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,242,061		2,641,511
Cash and cash equivalents	1,110,892		688,783
Deferred taxes	115,731		112,333
Operating lease right-of-use assets	63,825		0
Mortgage Banking:
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	567,754		524,422
Cash and cash equivalents	29,412		23,092
Operating lease right-of-use assets	13,345		0
Profit before taxes:
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,447,015		2,303,723
Profit before taxes: | Homebuilding: | Mid Atlantic
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,024,996		1,018,953
Profit before taxes: | Homebuilding: | North East
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	166,860		144,412
Profit before taxes: | Homebuilding: | Mid East
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	293,773		290,815
Profit before taxes: | Homebuilding: | South East
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	400,979		332,468
Profit before taxes: | Mortgage Banking:
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	560,407		517,075
Reconciling items:
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,362,800		862,210
Cash and cash equivalents	1,110,892		688,783
Deferred taxes	115,731		112,333
Intangible assets and goodwill	49,834		49,989
Operating lease right-of-use assets	63,825		0
Contract land deposit reserve	(27,572)		(29,216)
Consolidation adjustments and other	$ 50,090		$ 40,321