| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | NORTHWEST BANCSHARES, INC. |
| Entity Central Index Key | 0001471265 |
| Pay vs Performance Disclosure | 12 Months Ended | ||
| Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | Pay Versus Performance In accordance with rules adopted by the Securities and Exchange Commission (“SEC”) pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, we provide the following disclosure regarding executive “compensation actually paid” (“CAP”) and certain Northwest Bancshares, Inc. performance for the fiscal years listed below. You should refer to our Compensation Discussion & Analysis (“CD&A”) for a complete description of how executive compensation relates to Northwest Bancshares, Inc. performance and how the Compensation Committee makes its decisions. Principal Executive Officer (“PEO”)(1) Non-PEO Value of initial fixed $100 investment based on: Summary compensation on table total Compensation actually paid (3) Average summary compensation on table total ($) Average compensation actually paid ($) Total shareholder return ($) Peer group total shareholder return ($)(5) Company metrics Year 1st PEO ($) 2nd PEO ($)(4) 1st PEO ($) 2nd PEO ($) Net income (in thousands)($) Return on average assets (“ROA”) 2022 802,002 1,190,891 580,603 1,255,743 862,057 933,361 101.06 107.54 133,666 0.94 % 2021 1,688,530 — 1,758,462 — 730,276 793,259 96.62 128.28 154,323 1.08 % 2020 1,558,296 — 1,498,796 — 730,029 624,237 82.01 90.81 74,854 0.58 % (1) Mr. Seiffert served as Chairman, President and CEO during the years presented until his death on May 24, 2022. At this time, Mr. Harvey was appointed interim President and CEO. On August 17, 2022, Mr. Torchio was appointed P resid non-PEO non-PEO (2) Non-PEO (3) The following tables provides a reconciliation between the summary compensation on table total and the compensation actually paid: 1st PEO 2nd PEO Non-PEO Adjustments from Summary Compensation Table total 2022 2021 2020 2022 2021 2020 2022 2021 2020 Deduction for change in actuarial present values reported under the “Change in Pension Value and Non-qualified $ — (137,564 ) (145,802 ) $ (13,422 ) — — $ (5,165 ) (37,407 ) (112,070 ) Increase for service cost of pension plans — 125,912 123,751 34,469 — — 34,476 49,157 50,293 Increase/deduction for prior service cost of pension plans — — — — — — — — — Deduction for amounts reported under the “Stock Awards” and “Option Awards” columns in the Summary Compensation Table (460,279 ) (196,620 ) (112,358 ) (151,159 ) — — (163,187 ) (109,081 ) (63,358 ) Increase based on fair value of awards granted during year that remain unvested as of year-end, year-end — 165,456 142,627 176,755 — — 187,724 92,029 80,413 Increase/deduction for change in fair value from prior year-end year-end year-end — 47,665 (76,589 ) 13,591 — — 13,133 30,379 (58,861 ) Increase based on fair value of awards granted during year that vested during year, determined as of vesting date 273,656 36,252 16,390 — — — — 19,836 9,251 Increase/deduction for change in fair value from prior year-end (46,666 ) 7,331 (23,366 ) (6,270 ) — — (7,086 ) 4,978 (22,080 ) Deduction of fair value of awards granted prior to year that were forfeited during year — — — — — — — — — Increase based on dividends or other earnings paid during year prior to vesting date of award 11,890 21,500 15,847 10,888 — — 11,409 13,092 10,620 Total adjustments $ (221,399 ) 69,932 (59,500 ) $ 64,852 — — $ 71,304 62,983 (105,792 ) (4) Mr. Torchio was appointed as the CEO during 2022. The above disclosure includes salary of $270,769 for his service as the CEO and $258,779 for his service prior to becoming the CEO. (5) Peer group total shareholder return reflects the value of $100 investment in the NASDAQ Bank Index. | ||
| Company Selected Measure Name | ROA | ||
| Named Executive Officers, Footnote [Text Block] | Non-PEO | ||
| Peer Group Issuers, Footnote [Text Block] | Peer group total shareholder return reflects the value of $100 investment in the NASDAQ Bank Index. | ||
| Adjustment To PEO Compensation, Footnote [Text Block] | (3) The following tables provides a reconciliation between the summary compensation on table total and the compensation actually paid: 1st PEO 2nd PEO Non-PEO Adjustments from Summary Compensation Table total 2022 2021 2020 2022 2021 2020 2022 2021 2020 Deduction for change in actuarial present values reported under the “Change in Pension Value and Non-qualified $ — (137,564 ) (145,802 ) $ (13,422 ) — — $ (5,165 ) (37,407 ) (112,070 ) Increase for service cost of pension plans — 125,912 123,751 34,469 — — 34,476 49,157 50,293 Increase/deduction for prior service cost of pension plans — — — — — — — — — Deduction for amounts reported under the “Stock Awards” and “Option Awards” columns in the Summary Compensation Table (460,279 ) (196,620 ) (112,358 ) (151,159 ) — — (163,187 ) (109,081 ) (63,358 ) Increase based on fair value of awards granted during year that remain unvested as of year-end, year-end — 165,456 142,627 176,755 — — 187,724 92,029 80,413 Increase/deduction for change in fair value from prior year-end year-end year-end — 47,665 (76,589 ) 13,591 — — 13,133 30,379 (58,861 ) Increase based on fair value of awards granted during year that vested during year, determined as of vesting date 273,656 36,252 16,390 — — — — 19,836 9,251 Increase/deduction for change in fair value from prior year-end (46,666 ) 7,331 (23,366 ) (6,270 ) — — (7,086 ) 4,978 (22,080 ) Deduction of fair value of awards granted prior to year that were forfeited during year — — — — — — — — — Increase based on dividends or other earnings paid during year prior to vesting date of award 11,890 21,500 15,847 10,888 — — 11,409 13,092 10,620 Total adjustments $ (221,399 ) 69,932 (59,500 ) $ 64,852 — — $ 71,304 62,983 (105,792 ) | ||
| Non-PEO NEO Average Total Compensation Amount | $ 862,057 | $ 730,276 | $ 730,029 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 933,361 | 793,259 | 624,237 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | (3) The following tables provides a reconciliation between the summary compensation on table total and the compensation actually paid: 1st PEO 2nd PEO Non-PEO Adjustments from Summary Compensation Table total 2022 2021 2020 2022 2021 2020 2022 2021 2020 Deduction for change in actuarial present values reported under the “Change in Pension Value and Non-qualified $ — (137,564 ) (145,802 ) $ (13,422 ) — — $ (5,165 ) (37,407 ) (112,070 ) Increase for service cost of pension plans — 125,912 123,751 34,469 — — 34,476 49,157 50,293 Increase/deduction for prior service cost of pension plans — — — — — — — — — Deduction for amounts reported under the “Stock Awards” and “Option Awards” columns in the Summary Compensation Table (460,279 ) (196,620 ) (112,358 ) (151,159 ) — — (163,187 ) (109,081 ) (63,358 ) Increase based on fair value of awards granted during year that remain unvested as of year-end, year-end — 165,456 142,627 176,755 — — 187,724 92,029 80,413 Increase/deduction for change in fair value from prior year-end year-end year-end — 47,665 (76,589 ) 13,591 — — 13,133 30,379 (58,861 ) Increase based on fair value of awards granted during year that vested during year, determined as of vesting date 273,656 36,252 16,390 — — — — 19,836 9,251 Increase/deduction for change in fair value from prior year-end (46,666 ) 7,331 (23,366 ) (6,270 ) — — (7,086 ) 4,978 (22,080 ) Deduction of fair value of awards granted prior to year that were forfeited during year — — — — — — — — — Increase based on dividends or other earnings paid during year prior to vesting date of award 11,890 21,500 15,847 10,888 — — 11,409 13,092 10,620 Total adjustments $ (221,399 ) 69,932 (59,500 ) $ 64,852 — — $ 71,304 62,983 (105,792 ) | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | CAP and Company Cumulative TSR | ||
| Compensation Actually Paid vs. Net Income [Text Block] | CAP and Company Net Inc om | ||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | CAP and Company Return on Assets | ||
| Total Shareholder Return Vs Peer Group [Text Block] | Company and Peer Group Cumulati ve TS | ||
| Tabular List [Table Text Block] | In our assessment, the most important financial performance measures used to link CAP, as calculated in accordance with the SEC rules, to our NEOs in 2022 to our performance were: • Return on assets; • Return on equity; and • Efficiency ratio. | ||
| Total Shareholder Return Amount | $ 101.06 | 96.62 | 82.01 |
| Peer Group Total Shareholder Return Amount | 107.54 | 128.28 | 90.81 |
| Net Income (Loss) | $ 133,666,000 | $ 154,323,000 | $ 74,854,000 |
| Company Selected Measure Amount | 0.94 | 1.08 | 0.58 |
| SalaryforServiceasCEO | $ 270,769 | ||
| SalaryforServicePriortoBecomingCEO | $ 258,779 | ||
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Return on assets | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Return on equity | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Efficiency ratio | ||
| Mr. Seiffert [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| PEO Total Compensation Amount | $ 802,002 | $ 1,688,530 | $ 1,558,296 |
| PEO Actually Paid Compensation Amount | $ 580,603 | 1,758,462 | 1,498,796 |
| PEO Name | Mr. Seiffert’s | ||
| Mr. Torchio [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| PEO Total Compensation Amount | $ 1,190,891 | ||
| PEO Actually Paid Compensation Amount | $ 1,255,743 | ||
| PEO Name | Mr. Torchio’s | ||
| PEO [Member] | Mr. Seiffert [Member] | Change in Pension Value and Nonqualified Deferred Compensation Earnings [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 0 | (137,564) | (145,802) |
| PEO [Member] | Mr. Seiffert [Member] | service cost of pension plans [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 125,912 | 123,751 |
| PEO [Member] | Mr. Seiffert [Member] | prior service cost of pension plans [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Mr. Seiffert [Member] | StockAwardsAndOptionAwards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (460,279) | (196,620) | (112,358) |
| PEO [Member] | Mr. Seiffert [Member] | FairValueOfAwardsGrantedDuringYearThatRemainUnvestedAsOfYeaRendDeterminedAsOfYearEnd [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 165,456 | 142,627 |
| PEO [Member] | Mr. Seiffert [Member] | FairValueFromPriorYearendToCurrentYearEndOfAwardsGrantedPriorToYearThatWereOutstandingAndUnvestedAsOfYearEnd [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 47,665 | (76,589) |
| PEO [Member] | Mr. Seiffert [Member] | FairValueOfAwardsGrantedDuringYearThatVestedDuringYearDeterminedAsOfVestingDate [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 273,656 | 36,252 | 16,390 |
| PEO [Member] | Mr. Seiffert [Member] | FairValueFromPriorYearEndToVestingDateOfAwardsGrantedPriorToYearThatVestedDuringYear [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (46,666) | 7,331 | (23,366) |
| PEO [Member] | Mr. Seiffert [Member] | FairValueOfAwardsGrantedPriorToYearThatWereForfeitedDuringYear [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Mr. Seiffert [Member] | OtherEarningsPaidDuringYearPriorToVestingDateOfAward [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 11,890 | 21,500 | 15,847 |
| PEO [Member] | Mr. Seiffert [Member] | TotalAdjustments [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (221,399) | 69,932 | (59,500) |
| PEO [Member] | Mr. Torchio [Member] | Change in Pension Value and Nonqualified Deferred Compensation Earnings [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (13,422) | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | service cost of pension plans [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 34,469 | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | prior service cost of pension plans [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | StockAwardsAndOptionAwards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (151,159) | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | FairValueOfAwardsGrantedDuringYearThatRemainUnvestedAsOfYeaRendDeterminedAsOfYearEnd [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 176,755 | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | FairValueFromPriorYearendToCurrentYearEndOfAwardsGrantedPriorToYearThatWereOutstandingAndUnvestedAsOfYearEnd [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 13,591 | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | FairValueOfAwardsGrantedDuringYearThatVestedDuringYearDeterminedAsOfVestingDate [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | FairValueFromPriorYearEndToVestingDateOfAwardsGrantedPriorToYearThatVestedDuringYear [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (6,270) | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | FairValueOfAwardsGrantedPriorToYearThatWereForfeitedDuringYear [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | OtherEarningsPaidDuringYearPriorToVestingDateOfAward [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 10,888 | 0 | 0 |
| PEO [Member] | Mr. Torchio [Member] | TotalAdjustments [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 64,852 | 0 | 0 |
| Non-PEO NEO [Member] | Change in Pension Value and Nonqualified Deferred Compensation Earnings [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (5,165) | (37,407) | (112,070) |
| Non-PEO NEO [Member] | service cost of pension plans [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 34,476 | 49,157 | 50,293 |
| Non-PEO NEO [Member] | prior service cost of pension plans [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | StockAwardsAndOptionAwards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (163,187) | (109,081) | (63,358) |
| Non-PEO NEO [Member] | FairValueOfAwardsGrantedDuringYearThatRemainUnvestedAsOfYeaRendDeterminedAsOfYearEnd [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 187,724 | 92,029 | 80,413 |
| Non-PEO NEO [Member] | FairValueFromPriorYearendToCurrentYearEndOfAwardsGrantedPriorToYearThatWereOutstandingAndUnvestedAsOfYearEnd [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 13,133 | 30,379 | (58,861) |
| Non-PEO NEO [Member] | FairValueOfAwardsGrantedDuringYearThatVestedDuringYearDeterminedAsOfVestingDate [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 19,836 | 9,251 |
| Non-PEO NEO [Member] | FairValueFromPriorYearEndToVestingDateOfAwardsGrantedPriorToYearThatVestedDuringYear [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (7,086) | 4,978 | (22,080) |
| Non-PEO NEO [Member] | FairValueOfAwardsGrantedPriorToYearThatWereForfeitedDuringYear [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | OtherEarningsPaidDuringYearPriorToVestingDateOfAward [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 11,409 | 13,092 | 10,620 |
| Non-PEO NEO [Member] | TotalAdjustments [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 71,304 | $ 62,983 | $ (105,792) |
