Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Net Contract Land Deposit Impairment Recoveries	$ 5,115,000
Cash	732,248,000	$ 689,557,000	$ 416,037,000		$ 450,794,000
Contract land deposit impairments (recoveries), net	11,760,000	1,238,000	(4,269,000)
Contract land deposit assets impairment valuation allowances	29,216,000	29,999,000
Excess tax benefits from equity-based compensation	77,478,000	58,681,000	0
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	$ 138,246,000	150,033,000
Cash	688,783,000	645,087,000
Impairment of goodwill	0
Homebuilding: | Heartland Homes Inc
Significant Accounting Policies [Line Items]
Finite-lived intangibles acquired from business acquisition, net of accumulated amortization	$ 621,000	776,000
Weighted average life of finite-lived intangible assets	4 years
Goodwill acquired from business acquisition	$ 441,000	441,000
Mortgage Banking:
Significant Accounting Policies [Line Items]
Cash	$ 23,092,000	21,707,000
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]
Notional or Principal Amount	$ 682,152,000
Mortgage Banking: | Level 2 | Fair Value, Measurements, Recurring | Forward sales contracts
Significant Accounting Policies [Line Items]
Notional or Principal Amount	1,089,923,000
Consolidated Joint Venture
Significant Accounting Policies [Line Items]
Cash	320,000	1,069,000	$ 1,214,000
Other Assets
Significant Accounting Policies [Line Items]
Capitalized Contract Cost, Net	$ 17,000,000	$ 19,500,000
Scenario, Forecast [Member] | Accounting Standards Update 2016-02 [Member]
Significant Accounting Policies [Line Items]
Cumulative-effect adjustment from adoption of ASU 2016-09, net of tax				$ 0