Variable Interest Entities - Additional Information (Detail) $ in Thousands	Dec. 31, 2017 USD ($) lot	Dec. 31, 2016 USD ($)
Variable Interest Entity [Line Items]
Maximum range of deposits required under the purchase agreements	10.00%
Contract land deposits in cash	$ 400,428	$ 411,150
Variable Interest Entities
Variable Interest Entity [Line Items]
Maximum range of deposits required under the purchase agreements	10.00%
Lots controlled by NVR | lot	84,300
Contract land deposits in cash under Lot Purchase Agreements	$ 393,900
Letters of credit related to lots	$ 1,900
Contract on Raw Ground with Landowners
Variable Interest Entity [Line Items]
Lots controlled by NVR | lot	10,700
Contract land deposits in cash	$ 6,600
Letters of credit on raw land contracts	100
Refundable deposits	$ 5,800