Segment Disclosures - Income before Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	$ 267,174	$ 249,710	$ 730,493	$ 682,294
Equity-based compensation expense (1)			(58,680)	(51,690)
Corporate interest expense	(6,293)	(6,197)	(18,809)	(18,808)
Home Building [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	245,774	224,196	653,834	616,032
Corporate interest expense	(6,008)	(5,968)	(18,034)	(18,022)
Mortgage Banking [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	21,400	25,514	76,659	66,262
Corporate interest expense	(285)	(229)	(775)	(786)
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	250,830	244,093	694,378	643,902
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	124,900	115,180	348,067	318,447
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	13,164	18,560	36,187	51,041
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	50,210	51,744	125,976	121,129
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	39,721	31,426	105,582	83,867
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	22,835	27,183	78,566	69,418
Corporate and Reconciling Items [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income before taxes	16,344	5,617	36,115	38,392
Equity-based compensation expense (1)	(20,770)	(23,586)	(58,680)	(51,690)
Corporate capital allocation	57,887	55,438	168,621	160,091
Unallocated corporate overhead	(27,914)	(20,424)	(89,003)	(74,211)
Consolidation adjustments and other	13,107	142	33,141	22,173
Corporate interest expense	(5,966)	(5,953)	(17,964)	(17,971)
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	31,504	31,733	93,297	93,682
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	5,028	4,565	14,381	13,325
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	9,791	9,541	28,303	26,571
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	$ 11,564	$ 9,599	$ 32,640	$ 26,513