Note 4 - Real Estate Inventories - Real Estate Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deposits and pre-acquisition costs	$ 17,865	$ 20,726
Land held and land under development	180,823	210,527
Homes completed or under construction	183,711	286,416
Model homes	51,539	48,621
Real estate inventories	$ 433,938	$ 566,290

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

No definition available.

Name:	nwhm_InventoryRealEstateDepositsAndPreacquisitionCosts
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=6877327&loc=d3e13212-122682

+ Details

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