Real Estate Inventories and Capitalized Interest (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Real Estate [Abstract]
Deposits and pre-acquisition costs	$ 35,846	$ 38,723
Land held and land under development	47,757	98,596
Homes completed or under construction	302,884	93,628
Model homes	29,656	55,981
Real estate inventories	416,143	286,928
Deposits and pre-acquisition costs, refundable	$ 800	$ 4,100

Inventory, Real Estate, Deposits and Pre-Acquisition Costs

No definition available.

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

- Definition

Inventory, Real Estate, Deposits and Pre-Acquisition Costs, Refundable

+ References

No definition available.

+ Details

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

- Definition

Inventory, Real Estate, Homes Finished or Construction in Progress

+ References

No definition available.

+ Details

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

- Definition

Inventory, Real Estate, 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://www.xbrl.org/2003/role/presentationRef
-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

- References

No definition available.

+ Details

Name:	us-gaap_RealEstateAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration