Segment Disclosures - Income before Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	$ 209,831	$ 244,712	$ 371,206	$ 463,319
Contract land deposit reserve adjustment	900		37,300
Equity-based compensation expense (2)			(21,926)	(37,910)
Corporate interest expense	(9,525)	(6,301)	(16,011)	(12,516)
Home Building [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	194,805	219,650	344,724	408,060
Corporate interest expense	(9,166)	(6,033)	(15,380)	(12,026)
Mortgage Banking [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	15,026	25,062	26,482	55,259
Corporate interest expense	(359)	(268)	(631)	(490)
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	190,484	232,654	372,495	443,547
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	98,067	123,802	179,740	223,166
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	6,658	11,563	16,809	23,023
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	27,302	40,291	58,466	75,766
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	42,765	30,825	89,909	65,861
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	15,692	26,173	27,571	55,731
Corporate and Reconciling Items [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	19,347	12,058	(1,289)	19,772
Contract land deposit reserve adjustment	(460)	374	(36,075)	1,324
Equity-based compensation expense (2)	(14,434)	(18,577)	(21,926)	(37,910)
Corporate capital allocation	59,870	56,177	116,521	110,735
Unallocated corporate overhead	(23,288)	(29,354)	(60,927)	(61,089)
Consolidation adjustments and other	6,803	9,462	16,456	18,710
Corporate interest expense	(9,144)	(6,024)	(15,338)	(11,998)
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	31,581	31,378	61,336	61,794
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	5,790	4,626	11,349	9,353
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	9,687	9,497	19,050	18,512
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	$ 12,812	$ 10,676	$ 24,786	$ 21,076