Joint Ventures - Additional Information (Detail) $ in Thousands	Sep. 30, 2020 USD ($) lot joint_venture	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)
Joint Ventures [Line Items]
Aggregate investment	$ 28,700
Number of joint ventures | joint_venture	4
Expected production of finished lots | lot	6,050
Total lots controlled by company under the joint venture | lot	2,700
Total lots either under contract with unrelated parties or not under the current contract | lot	3,350
Additional funding commitments in the aggregate	$ 3,800
Number of joint ventures with additional funding commitment | joint_venture	1
Number of joint ventures NVR is not primary beneficiary | joint_venture	3
Other Assets [Member]
Joint Ventures [Line Items]
Aggregate investment	$ 28,700	$ 26,700
Home Building [Member]
Joint Ventures [Line Items]
Restricted cash and cash equivalents	28,026	17,943
Accrued expenses and other liabilities	387,757	346,035
Consolidated Joint Venture [Member] | Home Building [Member] | Other Assets [Member]
Joint Ventures [Line Items]
Restricted cash and cash equivalents	271	$ 281	$ 293	$ 320
Consolidated Joint Venture [Member] | Home Building [Member] | Accounts Payable and Accrued Liabilities [Member]
Joint Ventures [Line Items]
Accrued expenses and other liabilities	$ 247