EMPLOYEE BENEFITS (Asset Allocation) (Details) - Pension Benefits - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 128,430	$ 106,600	$ 102,800
Actual % of total	100.00%	100.00%
Fixed maturity securities - corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 9,451	$ 6,894
Actual % of total	7.40%	6.50%
Target allocation, minimum percentage	0.00%
Target allocation, maximum percentage	15.00%
Redeemable preferred stock
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 3,144	$ 3,744
Actual % of total	2.40%	3.50%
Target allocation, minimum percentage	0.00%
Target allocation, maximum percentage	10.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 69,770	$ 58,613
Actual % of total	54.30%	55.00%
Target allocation, minimum percentage	50.00%
Target allocation, maximum percentage	70.00%
Core plus bond separate account fund
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 10,401	$ 6,605
Actual % of total	8.10%	6.20%
Target allocation, minimum percentage	0.00%
Target allocation, maximum percentage	40.00%
U.S. property separate account fund
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 14,330	$ 11,252
Actual % of total	11.10%	10.50%
Target allocation, minimum percentage	0.00%
Target allocation, maximum percentage	25.00%
Arbitrage fund
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 8,292	$ 7,856
Actual % of total	6.50%	7.40%
Target allocation, minimum percentage	0.00%
Target allocation, maximum percentage	10.00%
United Life annuity
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 9,377	$ 8,931
Actual % of total	7.30%	8.40%
Target allocation, minimum percentage	5.00%
Target allocation, maximum percentage	10.00%
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 3,665	$ 2,705
Actual % of total	2.90%	2.50%
Target allocation, minimum percentage	0.00%
Target allocation, maximum percentage	10.00%