EMPLOYEE BENEFIT PLANS - Fair Value of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash and cash equivalents | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	$ 883	$ 917
Equity securities: U.S. large-cap growth | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	17,977	19,147
Equity securities: U.S. large-cap value | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	17,635	19,196
Equity securities: U.S. small/mid-cap blend | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	7,609	8,681
Equity securities: International large-cap core | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	3,257	2,934
Fixed income securities: U.S. Treasury securities | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	1,234	1,455
Fixed income securities: Corporate bonds | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	1,938	1,802
Fixed income securities: Preferred stock | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets		61
Fixed income securities: Taxable municipal bonds | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	182	193
Fixed income securities: International bonds | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	319	227
Equity mutual funds: U.S. mid-cap growth | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	4,948	2,537
Equity mutual funds: International | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	3,322	2,856
Fixed income mutual funds: Corporate bond | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	4,668	4,729
Fixed income mutual funds: Mortgage backed-securities | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	1,277	1,226
Fixed income mutual funds: Short term investment grade bond | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	1,322	1,417
Fixed income mutual funds: Intermediate investment grade bond | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	801	1,013
Fixed income mutual funds: High yield bond | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	693	689
Fixed income mutual funds: International bond | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	226	296
Stock market index options: Puts | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	143	111
Stock market index options: Calls | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	(54)	(40)
Accrued income | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	65	74
Pension Plan
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	68,445	69,521	$ 67,480
Pension Plan | Level 1
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	48,684	52,401
Pension Plan | Level 2
Employee Benefit Plans
Defined benefit plan, fair value of plan assets	$ 19,761	$ 17,120
Pension Plan | Fixed income securities: Corporate bonds | Maximum
Employee Benefit Plans
Percentage of securities below investment grade	5.00%	5.00%