Joint Ventures - Additional Information (Detail) $ in Thousands	Mar. 31, 2018 USD ($) lot joint_venture	Dec. 31, 2017 USD ($)
Joint Ventures [Line Items]
Aggregate investment | $	$ 43,000
Number of joint ventures | joint_venture	6
Expected production of finished lots | lot	7,200
Total lots controlled by company under the joint venture | lot	3,800
Total lots either under contract with unrelated parties or not under the current contract | lot	3,400
Additional funding commitments in the aggregate | $	$ 5,300
Number of joint ventures with additional funding commitment | joint_venture	3
Number of joint ventures NVR is not primary beneficiary | joint_venture	5
Other Assets [Member]
Joint Ventures [Line Items]
Aggregate investment | $	$ 42,600	$ 49,000