EMPLOYEE RETIREMENT PLANS - Schedule of fair value hierarchy (Details) - Plan Assets [Member] - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018 |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | $ 41,036 | $ 37,353 |
Subtotal [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 40,945 | 37,247 |
Common stocks [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 17,490 | 15,160 |
Preferred stocks [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 316 | 307 |
Exchange traded funds [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 5,213 | 4,454 |
Corporate obligations [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 4,626 | 4,568 |
State and municipal obligations [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 1,062 | 1,046 |
Pooled fixed income funds [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 7,598 | 7,767 |
U.S. government securities [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 364 | 286 |
Marketable CD's [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 806 | 911 |
Cash and cash equivalents [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 3,470 | 2,748 |
Other assets [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 91 | 106 |
Fair Value, Inputs, Level 1 [Member] | Subtotal [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 32,032 | 28,804 |
Fair Value, Inputs, Level 1 [Member] | Common stocks [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 15,464 | 13,556 |
Fair Value, Inputs, Level 1 [Member] | Preferred stocks [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 287 | 279 |
Fair Value, Inputs, Level 1 [Member] | Exchange traded funds [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 5,213 | 4,454 |
Fair Value, Inputs, Level 1 [Member] | Corporate obligations [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | State and municipal obligations [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Pooled fixed income funds [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 7,598 | 7,767 |
Fair Value, Inputs, Level 1 [Member] | U.S. government securities [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Marketable CD's [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Cash and cash equivalents [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 3,470 | 2,748 |
Fair Value, Inputs, Level 2 [Member] | Subtotal [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 8,913 | 8,443 |
Fair Value, Inputs, Level 2 [Member] | Common stocks [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 2,026 | 1,604 |
Fair Value, Inputs, Level 2 [Member] | Preferred stocks [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 29 | 28 |
Fair Value, Inputs, Level 2 [Member] | Exchange traded funds [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Corporate obligations [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 4,626 | 4,568 |
Fair Value, Inputs, Level 2 [Member] | State and municipal obligations [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 1,062 | 1,046 |
Fair Value, Inputs, Level 2 [Member] | Pooled fixed income funds [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | U.S. government securities [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 364 | 286 |
Fair Value, Inputs, Level 2 [Member] | Marketable CD's [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 806 | 911 |
Fair Value, Inputs, Level 2 [Member] | Cash and cash equivalents [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Subtotal [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Common stocks [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Preferred stocks [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Exchange traded funds [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Corporate obligations [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | State and municipal obligations [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Pooled fixed income funds [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | U.S. government securities [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Marketable CD's [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Cash and cash equivalents [Member] | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair Value of Pension Plan Assets, Total | $ 0 | $ 0 |