Segment Information, Nature of Operations, and Certain Concentrations - Revenues (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Consolidated revenues									$ 7,536,923	$ 7,388,664	$ 7,163,674
Home Building
Segment Reporting, Revenue Reconciling Item [Line Items]
Consolidated revenues	$ 2,263,673	$ 1,920,751	$ 1,588,758	$ 1,555,707	$ 1,946,859	$ 1,873,331	$ 1,757,448	$ 1,643,206	7,328,889	7,220,844	7,004,304
Home Building | Mid Atlantic
Segment Reporting, Revenue Reconciling Item [Line Items]
Consolidated revenues									3,668,542	3,901,573	3,893,358
Home Building | North East
Segment Reporting, Revenue Reconciling Item [Line Items]
Consolidated revenues									538,772	514,804	580,726
Home Building | Mid East
Segment Reporting, Revenue Reconciling Item [Line Items]
Consolidated revenues									1,524,667	1,501,139	1,455,834
Home Building | South East
Segment Reporting, Revenue Reconciling Item [Line Items]
Consolidated revenues									1,596,908	1,303,328	1,074,386
Mortgage Banking
Segment Reporting, Revenue Reconciling Item [Line Items]
Consolidated revenues	$ 80,342	$ 69,261	$ 31,610	$ 26,821	$ 43,336	$ 37,933	$ 42,746	$ 43,805	$ 208,034	$ 167,820	$ 159,370