Variable Interest Entities ("VIEs") - Additional Information (Detail) $ in Thousands	Sep. 30, 2018 USD ($) lot	Dec. 31, 2017 USD ($)
Variable Interest Entity [Line Items]
Contract land deposits in cash	$ 402,318	$ 400,428
Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Maximum range of deposits required under the purchase agreements	10.00%
Power of developers equity holders to direct operating activities of development entity	100.00%
Lots controlled by NVR | lot	92,350
Contract land deposits in cash under lot purchase Agreements	$ 398,800
Letters of credit related to lots	$ 3,800
Contract on Raw Ground with Landowners [Member]
Variable Interest Entity [Line Items]
Lots controlled by NVR | lot	7,800
Contract land deposits in cash	$ 3,500
Letters of credit related to land contract	100
Refundable deposits and letters of credit	$ 1,300