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PENSION AND OTHER BENEFIT PLANS - Funded status and amounts recognized in balance sheets and AOCI (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2009
Amounts recognized in accumulated other comprehensive loss/(income) ("AOCI") were: |  |  |  |
AOCI at year end | $ 31,301 | $ 15,470 | $ 28,873 |
Accumulated other comprehensive income (loss), negative postretirement medical plan amendment, arising during period, net of tax |  |  |  | $ 3,500
Pension Benefits |  |  |  |
Change in benefit obligation: |  |  |  |
Benefit obligation at the beginning of year | 183,270 | 190,361 |  |
Service cost | 4,959 | 5,920 | 5,750 |
Interest cost | 5,334 | 5,036 | 5,657 |
Plan amendment / acquisition | 1,851 | 0 |  |
Participant contributions | 0 | 0 |  |
Deferred actuarial (gain)/loss | (31,759) | (4,881) |  |
Benefits paid | (12,294) | (13,166) |  |
Benefit obligation at end of year | 151,361 | 183,270 | 190,361 |
Change in plan assets: |  |  |  |
Fair value of plan assets at beginning of year | 290,687 | 272,600 |  |
Actual return of plan assets | (34,967) | 27,614 |  |
Participant contributions | 0 | 0 |  |
Employer contributions | 906 | 3,639 |  |
Plan acquisition | 0 | 0 |  |
Benefits paid | (12,294) | (13,166) |  |
Fair value of plan assets at end of year | 244,332 | 290,687 | 272,600 |
Over/(Under) funded status at year end | 92,971 | 107,417 |  |
Amounts recognized in the consolidated statement of condition were: |  |  |  |
Other assets | 106,986 | 127,538 |  |
Other liabilities | (14,015) | (20,121) |  |
Amounts recognized in accumulated other comprehensive loss/(income) ("AOCI") were: |  |  |  |
Net loss | 38,894 | 16,977 |  |
Net prior service cost (credit) | 3,112 | 3,969 |  |
Pre-tax AOCI | 42,006 | 20,946 |  |
Taxes | (10,351) | (5,236) |  |
AOCI at year end | 31,655 | 15,710 |  |
Pension Benefits | Nonqualified Plan | Unfunded Plan |  |  |  |
Change in plan assets: |  |  |  |
Employer contributions | 100 | 2,900 |  |
Pension Benefits | Restoration Plan | Nonqualified Plan | Unfunded Plan |  |  |  |
Amounts recognized in accumulated other comprehensive loss/(income) ("AOCI") were: |  |  |  |
Initial projected benefit obligation |  | 300 |  |
Post-retirement Benefits |  |  |  |
Change in benefit obligation: |  |  |  |
Benefit obligation at the beginning of year | 1,529 | 1,718 |  |
Service cost | 0 | 0 | 0 |
Interest cost | 68 | 44 | 57 |
Plan amendment / acquisition | 536 | 0 |  |
Participant contributions | 0 | 0 |  |
Deferred actuarial (gain)/loss | (306) | (85) |  |
Benefits paid | (171) | (148) |  |
Benefit obligation at end of year | 1,656 | 1,529 | 1,718 |
Change in plan assets: |  |  |  |
Fair value of plan assets at beginning of year | 0 | 0 |  |
Actual return of plan assets | 0 | 0 |  |
Participant contributions | 0 | 0 |  |
Employer contributions | 171 | 148 |  |
Plan acquisition | 0 | 0 |  |
Benefits paid | (171) | (148) |  |
Fair value of plan assets at end of year | 0 | 0 | $ 0 |
Over/(Under) funded status at year end | (1,656) | (1,529) |  |
Amounts recognized in the consolidated statement of condition were: |  |  |  |
Other assets | 0 | 0 |  |
Other liabilities | (1,656) | (1,529) |  |
Amounts recognized in accumulated other comprehensive loss/(income) ("AOCI") were: |  |  |  |
Net loss | 255 | 585 |  |
Net prior service cost (credit) | (728) | (907) |  |
Pre-tax AOCI | (473) | (322) |  |
Taxes | 119 | 82 |  |
AOCI at year end | $ (354) | (240) |  |
Supplemental Pension Plans | Key Executives |  |  |  |
Pension Plans |  |  |  |
Defined Benefit Plan, Funding Status [Extensible List] | Unfunded Plan |  |  |
Change in benefit obligation: |  |  |  |
Benefit obligation at the beginning of year | $ 19,800 |  |  |
Benefit obligation at end of year | 14,000 | 19,800 |  |
Amounts recognized in accumulated other comprehensive loss/(income) ("AOCI") were: |  |  |  |
Benefit obligation for defined benefit pension plan prior to plan revaluation | $ 137,300 | $ 163,100 |  |

X
- Definition The tax on net gain (loss) on prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost. + References No definition available. + Details
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