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RETIREMENT PLANS: (Details 4) | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 100.00% | 100.00%
Employee Stock Ownership Plan |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 100.00% | 100.00%
Other securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 5.00% | 6.00%
Other securities | Employee Stock Ownership Plan |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 2.00% | 1.00%
Equity Securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 63.00% | 63.00%
Equity Securities | Minimum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 25.00% |
Equity Securities | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 75.00% |
Equity Securities | Employee Stock Ownership Plan |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 98.00% | 99.00%
Equity Securities | Employee Stock Ownership Plan | Minimum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 95.00% |
Equity Securities | Employee Stock Ownership Plan | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 99.00% |
Debt securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 32.00% | 31.00%
Debt securities | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 50.00% |
Debt securities | Employee Stock Ownership Plan |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 0.00% | 0.00%
Other Security Investments [Member] | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 20.00% |
Other Security Investments [Member] | Employee Stock Ownership Plan | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of plan assets (percent) | 5.00% |

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