Debt - Additional Information (Detail)	3 Months Ended
Mar. 31, 2019 USD ($)
Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Senior notes principal amount	$ 600,000,000
Senior notes maturity date	Sep. 15, 2022
Senior notes interest rate	3.95%
Frequency of senior notes payment	semi-annually in arrears on March 15 and September 15
Senior notes effective interest rate	3.97%
Credit Agreement [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum loan borrowing capacity	$ 200,000,000
Increase in commitment available	$ 300,000,000
Expiration date	Jul. 15, 2021
Debt outstanding	$ 0
Credit Agreement [Member] \| Revolving Credit Facility [Member] \| Sublimit for Issuance of Letters of Credit [Member]
Debt Instrument [Line Items]
Maximum loan borrowing capacity	100,000,000
Letters of credit outstanding	9,100,000
Credit Agreement [Member] \| Revolving Credit Facility [Member] \| Sublimit for Swing Line Commitment [Member]
Debt Instrument [Line Items]
Maximum loan borrowing capacity	25,000,000
Repurchase Agreement [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum loan borrowing capacity	$ 150,000,000
Expiration date	Jul. 24, 2019
Debt outstanding	$ 0
Borrowing base limitations	$ 0

The Maximum Incremental Commitment amount is the sum of all incremental commitments under the repurchase facility.

No definition available.

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Namespace Prefix:	nvr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
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-Section 55
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of the amount outstanding under the credit facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

Carrying value as of the balance sheet date of the outstanding short-term borrowings under a revolving line of credit used by mortgage bankers to finance the origination or purchase of loans.

+ References

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- Details

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- Details

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- Details

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Period Type:

- Details

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Namespace Prefix:
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- Details

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Period Type: