Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Significant Accounting Policies [Line Items]
Net Contract Land Deposit Impairment Recoveries		$ (5,115,000)
Contract land deposit (recoveries) impairments, net	$ (680,000)	11,760,000	$ 1,238,000
Contract land deposit assets impairment valuation allowances	27,572,000	29,216,000
Excess tax benefits from equity-based compensation	101,466,000	77,478,000	58,681,000
Operating activities	866,535,000	723,126,000	570,354,000
Financing activities	$ (424,695,000)	(672,258,000)	(281,641,000)
Cumulative-effect adjustment from adoption of ASU 2016-09, net of tax			2,196,000	$ 609,000
Retained Earnings
Significant Accounting Policies [Line Items]
Cumulative-effect adjustment from adoption of ASU 2016-09, net of tax			$ 2,196,000	$ (957,000)
Model home furniture and fixtures
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Office facilities and other | Minimum
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Office facilities and other | Maximum
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Manufacturing Facilities | Minimum
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Manufacturing Facilities | Maximum
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Homebuilding:
Significant Accounting Policies [Line Items]
Customer deposits	$ 131,886,000	138,246,000
Cash	1,110,892,000	688,783,000
Impairment of goodwill	0
Homebuilding: | Heartland Homes Inc
Significant Accounting Policies [Line Items]
Finite-lived intangibles acquired from business acquisition, net of accumulated amortization	$ 466,000	621,000
Weighted average life of finite-lived intangible assets	3 years
Goodwill acquired from business acquisition	$ 441,000	441,000
Mortgage Banking:
Significant Accounting Policies [Line Items]
Cash	$ 29,412,000	23,092,000
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]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	$ 581,065,000
Mortgage Banking: | Level 2 | Fair Value, Measurements, Recurring | Forward sales contracts
Significant Accounting Policies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	986,041,000
Consolidated Joint Venture
Significant Accounting Policies [Line Items]
Cash	281,000	320,000
Other Assets
Significant Accounting Policies [Line Items]
Capitalized Contract Cost, Net	$ 14,600,000	$ 17,000,000