Segment Disclosures - Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 3,009,395	$ 2,989,279
Contract land deposit reserve	(27,279)	(29,999)
Homebuilding [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,553,269	2,584,880
Cash and cash equivalents	417,341	645,087
Mortgage Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	456,126	404,399
Cash and cash equivalents	14,209	21,707
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,382,143	2,160,009
Operating Segments [Member] | Homebuilding [Member] | Mid Atlantic [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,139,958	1,079,225
Operating Segments [Member] | Homebuilding [Member] | North East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	155,089	143,008
Operating Segments [Member] | Homebuilding [Member] | Mid East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	322,718	263,019
Operating Segments [Member] | Homebuilding [Member] | South East [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	315,599	277,705
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	448,779	397,052
Corporate and Reconciling Items [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	627,252	829,270
Cash and cash equivalents	417,341	645,087
Deferred taxes	116,295	111,953
Intangible assets and goodwill	50,066	50,144
Contract land deposit reserve	(27,279)	(29,999)
Consolidation adjustments and other	$ 70,829	$ 52,085