Capitalized Interest - Summary of Interest Costs Incurred, Capitalized, Expensed and Charged to Cost of Sales (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Roll Forward]
Interest capitalized, beginning of period	$ 5,545	$ 5,564	$ 5,583	$ 5,106
Interest incurred	6,624	6,580	13,220	13,139
Interest expense	(6,329)	(5,914)	(12,611)	(11,750)
Interest charged to cost of sales	(452)	(278)	(804)	(543)
Interest capitalized, end of period	$ 5,388	$ 5,952	$ 5,388	$ 5,952

Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Roll Forward]

No definition available.

Name:	nvr_CapitalizedInterestCostsIncludingAllowanceforFundsUsedDuringConstructionRollForward
Namespace Prefix:	nvr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Total interest costs incurred during the period and either capitalized or charged against earnings.

+ References

+ Details

Name:	us-gaap_InterestCostsIncurred
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

Name:	us-gaap_InterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of interest costs that were capitalized to properties under development during the land development and construction period of a project, and which are included in inventory.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

+ Details

Name:	us-gaap_RealEstateInventoryCapitalizedInterestCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of interest cost charged to cost of sales that had been previously capitalized to inventory.

+ References

+ Details

Name:	us-gaap_RealEstateInventoryCapitalizedInterestCostsCostOfSales1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration