Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Significant Accounting Policies [Line Items]
Cash	$ 2,809,782	$ 1,160,804	$ 732,248	$ 689,557
Contract land deposit assets impairment valuation allowances	52,205	27,572
Net Contract Land Deposit Impairment Recoveries	$ 25,600	(700)	$ 5,100
Office facilities and other | Maximum
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Manufacturing Facilities | Maximum
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Home Building
Significant Accounting Policies [Line Items]
Cash	$ 2,714,720	1,110,892
Goodwill acquired from business acquisition	41,580	41,580
Contract with Customer, Liability	240,758	131,886
Mortgage Banking
Significant Accounting Policies [Line Items]
Cash	63,547	29,412
Goodwill acquired from business acquisition	$ 7,347	7,347
Mortgage Banking | Level 2 | Fair Value, Measurements, Recurring
Significant Accounting Policies [Line Items]
Typical length of days loans sold into secondary market	30 days
Mortgage Banking | Level 2 | Fair Value, Measurements, Recurring | Rate lock commitments
Significant Accounting Policies [Line Items]
Derivative, Notional Amount	$ 617,308
Mortgage Banking | Level 2 | Fair Value, Measurements, Recurring | Forward sales contracts
Significant Accounting Policies [Line Items]
Derivative, Notional Amount	916,588
Consolidated Joint Venture
Significant Accounting Policies [Line Items]
Cash	269	281
Other Assets
Significant Accounting Policies [Line Items]
Capitalized Contract Cost, Net	$ 22,500	$ 14,600