Segment Disclosures - Revenues (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 1,852,407	$ 1,667,920	$ 5,169,126	$ 4,489,504
Home Building [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	1,809,345	1,633,726	5,049,901	4,394,027
Home Building [Member] | Mid Atlantic [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	991,077	927,551	2,807,251	2,521,967
Home Building [Member] | North East [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	152,858	141,033	423,190	374,804
Home Building [Member] | Mid East [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	391,933	338,900	1,045,458	895,168
Home Building [Member] | South East [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	273,477	226,242	774,002	602,088
Mortgage Banking [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 43,062	$ 34,194	$ 119,225	$ 95,477