Related Party Transactions - Additional Information (Detail) - Elm Street $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) lot	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Related party forward lot purchase agreements purchase price | $	$ 138,100
Number of related parties for forward lot purchase agreement | lot	1
Market price of developed lots | $	$ 60,200	$ 44,600	$ 36,100
Expected number of lots from joint venture with Elm Street | lot	1,900