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

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount recognised as of the business combination's acquisition date for goodwill. [Refer: Goodwill; Business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 3
-IssueDate 2019-01-01
-Paragraph B64
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2019-en-r&anchor=para_B64&doctype=Appendix&subtype=B
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 3
-IssueDate 2019-01-01
-Paragraph IE72
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2019-en-r&anchor=para_IE72&doctype=Illustrative%20Examples
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_GoodwillRecognisedAsOfAcquisitionDate
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of impairment loss recognised in profit or loss for intangible assets and goodwill. [Refer: Impairment loss recognised in profit or loss; Intangible assets and goodwill]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 38
-IssueDate 2019-01-01
-Paragraph 118
-Subparagraph e
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2019-en-r&anchor=para_118_e_iv&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsAndGoodwill
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of expenditure directly attributable to research or development activities, recognised in profit or loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 38
-IssueDate 2019-01-01
-Paragraph 126
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2019-en-r&anchor=para_126&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_ResearchAndDevelopmentExpense
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ifrs-full_BusinessCombinationsAxis=ntz_TwoThousandSeventeenAcquisitionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BusinessCombinationsAxis=ntz_TwoThousandSixteenAcquisitionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Intangibles Assets and Goodwill - Additional Information (Detail) - EUR (€)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 31, 2017
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Impairment loss on intangible assets and goodwill	€ 0	€ 0
Research and development expense	€ 3,700,000	€ 3,362,000	€ 4,508,000
2017 Acquisitions [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Goodwill				€ 2,041,000
2016 Acquisitions [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Goodwill				€ 1,921,000