Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Other Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract cost	$ 27,513	$ 14,600
Home Building [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash and cash equivalents	28,026	17,943
Contract liabilities for customer deposits	211,122	131,886
Consolidated Joint Venture [Member] | Home Building [Member] | Other Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash and cash equivalents	$ 271	$ 281	$ 293	$ 320