CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Cash Flows [Abstract]
Interest on deposits and borrowings, interest credited to deposit accounts	$ 13,399	$ 18,711	$ 34,313

This element represents interest paid to depositors on deposit accounts held by the institution.

No definition available.

Name:	nwbi_CashPaidForInterestOnDeposits
Namespace Prefix:	nwbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration