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EMPLOYEE BENEFIT PLANS (Details Textual) | 12 Months Ended
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Dec. 31, 2017 USD ($) age shares | Dec. 31, 2016 USD ($) shares | Dec. 31, 2015 USD ($)
Defined Contribution Plan Disclosure [Line Items] |  |  |
Incentive plans and discretionary bonus expense | $ 10,900,000 | $ 10,300,000 | $ 10,300,000
Employer matching contribution percent | 25.00% |  |
Employee contribution percent | 6.00% |  |
Nondiscretionary requisite service period | 1 year |  |
Defined Contribution Plan, Nondiscretionary Requisite service hours | 1000 |  |
Nondiscretionary employer contribution, percent up to social security limit | 5.00% |  |
Nondiscretionary employer contribution, percent over social security limit | 10.00% |  |
Supplemental Unemployment Benefit, Salary Continuation Expense | $ 11,000 | 13,000 | 11,000
Deferred Compensation Arrangement with Individual, Contributions by Employer | $ 143,000 | 142,000 | 149,000
Multiemployer Plans [Abstract] |  |  |
Significance of contributions percentage | 5.00% |  |
Defined benefit plan expense | $ 1,900,000 | 2,000,000 | 1,600,000
Postretirement Benefits [Abstract] |  |  |
Retirement age | age | 65 |  |
Service period to be eligible for postretirement benefit | 10 years |  |
Death benefit | $ 5,000 |  |
Supplemental Executive Retirement Plans [Abstract] |  |  |
Plan assets | $ 16,200,000 | $ 16,000,000 |
Deferred Compensation Arrangements [Abstract] |  |  |
Deferred compensation, shares provided for the plan (in shares) | shares | 161,961 | 168,352 |
Deferred compensation, recorded liability | $ 4,500,000 | $ 4,200,000 |
401(k) Restoration Plan [Member] |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Defined contribution plan expense | 267,000 | 425,000 | 232,000
Employee Savings Plan [Member] |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Defined contribution plan expense | 5,000,000 | 4,800,000 | 4,500,000
Executive Vice President [Member] |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Supplemental Unemployment Benefits, Salary Continuation | 279,000 | 272,000 | 222,000
Director [Member] |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Supplemental Unemployment Benefits, Salary Continuation | $ 38,000 | $ 40,000 | $ 35,000

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