Note 4 - Real Estate Inventories - Real Estate Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deposits and pre-acquisition costs	$ 12,202	$ 17,865
Land held and land under development	127,807	180,823
Homes completed or under construction	133,567	183,711
Model homes	41,381	51,539
Inventory, Real Estate, Total	$ 314,957	$ 433,938

Represents the total amount of deposits and costs incurred before an acquisition takes place.

No definition available.

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Namespace Prefix:	nwhm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the carrying amount as of the balance sheet date of homes completed, and homes which are under construction.

+ References

No definition available.

+ Details

Name:	nwhm_InventoryRealEstateHomesCompletedOrUnderConstruction
Namespace Prefix:	nwhm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the carrying amount of model homes.

+ References

No definition available.

+ Details

Name:	nwhm_InventoryRealEstateModelHomes
Namespace Prefix:	nwhm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Total of (1) improvements, (2) held-for-sale, (3) land and land under development, (4) construction-in-process, (5) mortgage loans held-in-inventory, and (6) other real estate investments which are considered inventory due to being held for sale or disposition.

+ References

No definition available.

+ Details

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

- Definition

Carrying amount as of the balance sheet date, net of valuation allowances and impairment losses, of costs of land expected to be developed in the near term plus capitalized costs of development, for purposes of selling completed units to home buyers or commercial or industrial entities..

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Period Type:	instant