Basis of Presentation and Informational Disclosures (Details)	Jun. 30, 2024 bank_location
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of banking locations	139

Represents the number of banking locations in which the entity operates.

No definition available.

Name:	nwbi_NumberOfBankingLocations
Namespace Prefix:	nwbi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant