Segment Disclosures - Income before Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	$ 244,712	$ 241,586	$ 463,319	$ 432,584
Equity-based compensation expense (1)			(37,910)	(28,104)
Corporate interest expense	(6,301)	(6,329)	(12,516)	(12,611)
Home Building [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	219,650	223,266	408,060	391,836
Corporate interest expense	(6,033)	(6,047)	(12,026)	(12,054)
Mortgage Banking [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	25,062	18,320	55,259	40,748
Corporate interest expense	(268)	(282)	(490)	(557)
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	232,654	220,060	443,547	399,809
Operating Segments [Member] | Home Building [Member] | Mid Atlantic [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	123,802	112,221	223,166	203,268
Operating Segments [Member] | Home Building [Member] | North East [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	11,563	16,777	23,023	32,481
Operating Segments [Member] | Home Building [Member] | Mid East [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	40,291	42,174	75,766	69,385
Operating Segments [Member] | Home Building [Member] | South East [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	30,825	29,203	65,861	52,440
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	26,173	19,685	55,731	42,235
Corporate and Reconciling Items [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	12,058	21,526	19,772	32,775
Equity-based compensation expense (1)	(18,577)	(18,595)	(37,910)	(28,104)
Corporate capital allocation	56,177	53,954	110,735	104,653
Unallocated corporate overhead	(29,354)	(22,503)	(61,089)	(53,787)
Consolidation adjustments and other	9,836	14,701	20,034	22,031
Corporate interest expense	(6,024)	(6,031)	(11,998)	(12,018)
Corporate and Reconciling Items [Member] | Home Building [Member] | Mid Atlantic [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Corporate capital allocation	31,378	31,501	61,794	61,949
Corporate and Reconciling Items [Member] | Home Building [Member] | North East [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Corporate capital allocation	4,626	4,580	9,353	8,760
Corporate and Reconciling Items [Member] | Home Building [Member] | Mid East [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Corporate capital allocation	9,497	9,057	18,512	17,030
Corporate and Reconciling Items [Member] | Home Building [Member] | South East [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Corporate capital allocation	$ 10,676	$ 8,816	$ 21,076	$ 16,914