EMPLOYEE BENEFIT PLANS (Details Textual)	12 Months Ended
	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