Fair Value Disclosures - Summary of Nonfinancial Assets Measured at Fair Value on a Nonrecurring Basis (Detail)	12 Months Ended
	Dec. 31, 2019 USD ($) community	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Real estate inventory impairments	$ 10,078,000	$ 0	$ 854,000
Real estate inventories	$ 3,065,436,000	3,216,059,000
Number of impaired real estate properties | community	4
Fair Value Measurements Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Real estate inventory impairments	$ 9,735,000	0
Real estate inventories	$ 10,078,000	$ 0