EMPLOYEE BENEFIT PLANS (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) Portfolio Fund Participants shares	Dec. 31, 2017 USD ($) Participants shares	Dec. 31, 2016 USD ($) shares
Expected Future Benefit Payments [Abstract]
Proceeds from the sales of trading securities	$ 0	$ 4,629	$ 3,648
Tax benefit from market valuation adjustment on distribution of BMP ESOP shares			717
Employee Retirement Plan [Member]
Funded Status [Abstract]
Accumulated benefit obligation at end of period	23,047	26,029
Reconciliation of Projected benefit obligation [Roll Forward]
Projected benefit obligation at beginning of period	26,029	25,297
Interest cost	852	936	979
Actuarial (gain) loss	(2,293)	1,284
Benefit payments	(1,486)	(1,488)
Settlements	(55)	0
Projected benefit obligation at end of period	23,047	26,029	25,297
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	25,361	23,355
Return on plan assets	(1,296)	3,477
Contributions	33	17
Benefit payments	(1,486)	(1,488)
Settlements	(55)	0
Balance at end of period	22,557	25,361	23,355
Funded status at end of year	(490)	(668)
Net Periodic Cost [Abstract]
Interest cost	852	936	979
Expected return on plan assets	(1,719)	(1,579)	(1,532)
Amortization of unrealized loss	1,045	1,287	1,551
Net periodic cost	178	644	998
Change in Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance at beginning of period	(8,340)	(10,240)
Amortization of unrealized loss	1,045	1,287	1,551
Gain (loss) recognized during the year	(723)	613
Balance at the end of the period	(8,018)	(8,340)	$ (10,240)
Period end component of accumulated other comprehensive loss, net of tax	$ 5,456	$ 5,610
Assumptions Used in Calculations [Abstract]
Discount rate used for net periodic cost	3.38%	3.82%	3.98%
Discount rate used to determine benefit obligation at period end	4.04%	3.38%	3.82%
Expected long-term return on plan assets used for net periodic cost	7.00%	7.00%	7.00%
Expected long-term return on plan assets used to determine benefit obligation at period end	7.00%	7.00%	7.00%
Number of diversified investment portfolios | Portfolio	2
Percentage variance from the target allocation	10.00%
Number of registered mutual funds in LTGE diversified portfolio | Fund	7
Number of common collective trust funds in Long-Term Growth Equity diversified portfolio | Fund	6
Number of intermediate-term bond in Long-Term Growth Equity diversified portfolio | Fund	4
Weighted average allocation by asset category of the assets [Abstract]
Weighted average allocation by asset	100.00%	100.00%
Long-term inflation rate	2.50%
Expected rate of return	7.00%	7.00%
Expected contributions in the fiscal year	$ 32
Actuarial losses anticipated to be recognized as a component of net periodic cost	913
Expected Future Benefit Payments [Abstract]
2019	1,492
2020	1,486
2021	1,496
2022	1,471
2023	1,463
2024 to 2028	7,025
Bank contribution benefit payments	$ 33	$ 17
Employee Retirement Plan [Member] | Minimum [Member]
Employee Retirement Plan [Abstract]
Eligibility age	21 years
Eligibility service period	1 year
Employee Retirement Plan [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	$ 25,361
Balance at end of period	$ 22,557	$ 25,361
Employee Retirement Plan [Member] | Equity Securities [Member]
Assumptions Used in Calculations [Abstract]
Asset allocations target	65.00%
Weighted average allocation by asset category of the assets [Abstract]
Weighted average allocation by asset	58.00%	66.00%
Employee Retirement Plan [Member] | Equity Securities [Member] | Minimum [Member]
Weighted average allocation by asset category of the assets [Abstract]
Expected rate of return	5.00%
Employee Retirement Plan [Member] | Equity Securities [Member] | Maximum [Member]
Weighted average allocation by asset category of the assets [Abstract]
Expected rate of return	10.00%
Employee Retirement Plan [Member] | Debt Securities (Bond Mutual Fund) [Member]
Assumptions Used in Calculations [Abstract]
Asset allocations target	34.00%
Weighted average allocation by asset category of the assets [Abstract]
Weighted average allocation by asset	39.00%	32.00%
Employee Retirement Plan [Member] | Domestic Large Cap, Mutual Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	$ 3,228
Balance at end of period	2,546	$ 3,228
Employee Retirement Plan [Member] | Domestic Large Cap, Mutual Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Large Cap, Mutual Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Large Cap, Mutual Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	3,228
Balance at end of period	2,546	3,228
Employee Retirement Plan [Member] | Domestic Mid Cap, Mutual Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	1,344
Balance at end of period	1,080	1,344
Employee Retirement Plan [Member] | Domestic Mid Cap, Mutual Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Mid Cap, Mutual Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Mid Cap, Mutual Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	1,344
Balance at end of period	1,080	1,344
Employee Retirement Plan [Member] | Domestic Small Cap, Mutual Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	513
Balance at end of period	737	513
Employee Retirement Plan [Member] | Domestic Small Cap, Mutual Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Small Cap, Mutual Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Small Cap, Mutual Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	513
Balance at end of period	737	513
Employee Retirement Plan [Member] | International Equity, Mutual Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	3,198
Balance at end of period	2,507	3,198
Employee Retirement Plan [Member] | International Equity, Mutual Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | International Equity, Mutual Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | International Equity, Mutual Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	3,198
Balance at end of period	$ 2,507	3,198
Employee Retirement Plan [Member] | Fixed Income, Mutual Fund [Member] | Minimum [Member]
Weighted average allocation by asset category of the assets [Abstract]
Expected rate of return	1.00%
Employee Retirement Plan [Member] | Fixed Income, Mutual Fund [Member] | Maximum [Member]
Weighted average allocation by asset category of the assets [Abstract]
Expected rate of return	4.00%
Employee Retirement Plan [Member] | Fixed Income, Mutual Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	$ 8,133
Balance at end of period	8,756	8,133
Employee Retirement Plan [Member] | Fixed Income, Mutual Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Fixed Income, Mutual Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Fixed Income, Mutual Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	8,133
Balance at end of period	$ 8,756	$ 8,133
Employee Retirement Plan [Member] | Cash Equivalents, Mutual Fund [Member]
Assumptions Used in Calculations [Abstract]
Asset allocations target	1.00%
Weighted average allocation by asset category of the assets [Abstract]
Weighted average allocation by asset	3.00%	2.00%
Employee Retirement Plan [Member] | Cash Equivalents, Mutual Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	$ 510
Balance at end of period	650	$ 510
Employee Retirement Plan [Member] | Cash Equivalents, Mutual Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Cash Equivalents, Mutual Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Cash Equivalents, Mutual Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	510
Balance at end of period	650	510
Employee Retirement Plan [Member] | Domestic Large Cap, Common Collective Investment Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Large Cap, Common Collective Investment Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	5,246
Balance at end of period	4,295	5,246
Employee Retirement Plan [Member] | Domestic Large Cap, Common Collective Investment Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Large Cap, Common Collective Investment Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	5,246
Balance at end of period	4,295	5,246
Employee Retirement Plan [Member] | Domestic Mid Cap, Common Collective Trust Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Mid Cap, Common Collective Trust Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	702
Balance at end of period	550	702
Employee Retirement Plan [Member] | Domestic Mid Cap, Common Collective Trust Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Mid Cap, Common Collective Trust Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	702
Balance at end of period	550	702
Employee Retirement Plan [Member] | Domestic Small Cap, Common Collective Trust Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Small Cap, Common Collective Trust Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	1,527
Balance at end of period	844	1,527
Employee Retirement Plan [Member] | Domestic Small Cap, Common Collective Trust Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | Domestic Small Cap, Common Collective Trust Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	1,527
Balance at end of period	844	1,527
Employee Retirement Plan [Member] | International Equity, Common Collective Trust Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | International Equity, Common Collective Trust Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	960
Balance at end of period	592	960
Employee Retirement Plan [Member] | International Equity, Common Collective Trust Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0
Balance at end of period	0	0
Employee Retirement Plan [Member] | International Equity, Common Collective Trust Fund [Member] | Fair Value [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	960
Balance at end of period	592	960
BMP and the Director Retirement Plan [Member]
Funded Status [Abstract]
Accumulated benefit obligation at end of period	9,596	10,364
Reconciliation of Projected benefit obligation [Roll Forward]
Projected benefit obligation at beginning of period	10,364	11,351
Interest cost	313	379	$ 392
Actuarial (gain) loss	(311)	(822)
Benefit payments	(770)	(544)
Projected benefit obligation at end of period	9,596	10,364	11,351
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0	0
Contributions	770	544
Benefit payments	(770)	(544)
Balance at end of period	0	0	0
Funded status at end of year	(9,596)	(10,364)
Net Periodic Cost [Abstract]
Interest cost	313	379	392
Amortization of unrealized loss	109	147	161
Net periodic cost	422	526	553
Change in Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance at beginning of period	(1,789)	(2,758)
Amortization of unrealized loss	109	147	161
Gain (loss) recognized during the year	311	822
Balance at the end of the period	(1,369)	(1,789)	(2,758)
Period end component of accumulated other comprehensive loss, net of tax	1,089	1,203
Expected Future Benefit Payments [Abstract]
2019	789
2020	821
2021	813
2022	803
2023	793
2024 to 2028	3,909
Bank contribution benefit payments	770	544
Postretirement Benefit Plan [Member]
Funded Status [Abstract]
Accumulated benefit obligation at end of period	1,532	1,768
Reconciliation of Projected benefit obligation [Roll Forward]
Projected benefit obligation at beginning of period	1,768	1,756
Interest cost	54	59	63
Actuarial (gain) loss	(200)	132
Benefit payments	(90)	(179)
Projected benefit obligation at end of period	1,532	1,768	1,756
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Balance at beginning of period	0	0
Contributions	90	179
Benefit payments	(90)	(179)
Balance at end of period	0	0	0
Funded Status [Abstract]
Deficiency of plan assets over projected benefit obligation and accrued expense included in other liabilities	(1,532)	(1,768)
Net Periodic Cost [Abstract]
Interest cost	54	59	63
Amortization of unrealized loss	(9)	(14)	(12)
Net periodic cost	45	45	51
Change in Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance at beginning of period	203	349
Amortization of unrealized loss	(9)	(14)	(12)
Gain (loss) recognized during the year	200	(132)
Balance at the end of the period	394	203	$ 349
Period end component of accumulated other comprehensive loss, net of tax	$ (255)	$ (137)
Assumptions Used in Calculations [Abstract]
Discount rate used for net periodic cost	3.16%	3.48%	3.58%
Discount rate used to determine benefit obligation at period end	3.82%	3.16%	3.48%
Expected Future Benefit Payments [Abstract]
2019	$ 109
2020	101
2021	95
2022	89
2023	80
2024 to 2028	297
Bank contribution benefit payments	90	$ 179
Assumed Medical Care Cost Trend Rates [Abstract]
Increase the net periodic cost from an escalation in the assumed medical care cost trend rates by 1% in each year	1
Decrease the net periodic cost from a decline in the assumed medical care cost trend rates by 1% in each year	$ 1
Health care cost trend rate assumed for next fiscal year	6.50%
Ultimate health care cost trend rate	5.00%
Effect of one percentage point increase on accumulated postretirement benefit obligation	$ 22
Reduction in the accumulated Postretirement Benefit Plan obligation that would result from a decline in the assumed medical care cost trend rates by 1% in each year	20
Director Retirement Plan [Member]
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Contributions	$ 224
Assumptions Used in Calculations [Abstract]
Discount rate used for net periodic cost	3.17%	3.53%	3.67%
Discount rate used to determine benefit obligation at period end	3.84%	3.17%	3.53%
Weighted average allocation by asset category of the assets [Abstract]
Expected contributions in the fiscal year	$ 224
Actuarial losses anticipated to be recognized as a component of net periodic cost	$ 35
Expected Future Benefit Payments [Abstract]
Age of eligibility for outside director	75 years
Bank contribution benefit payments	$ 224
Defined contribution costs recognized	0
BMP [Member]
Employee Retirement Plan [Abstract]
Investment in holding company's common stock	2,334	$ 5,018
Plan assets at fair value (investments in trust funds managed by trustee) [Roll Forward]
Contributions	$ 546
Assumptions Used in Calculations [Abstract]
Discount rate used for net periodic cost	3.13%	3.46%	3.54%
Discount rate used to determine benefit obligation at period end	3.80%	3.13%	3.46%
Weighted average allocation by asset category of the assets [Abstract]
Expected contributions in the fiscal year	$ 546
Actuarial losses anticipated to be recognized as a component of net periodic cost	23
Expected Future Benefit Payments [Abstract]
Bank contribution benefit payments	$ 546
Number of participants that elected lump-sum distribution | Participants	3	3
Lump-sum distribution for retired participant	$ 2,477	$ 11,828	$ 7,736
Distribution of common stock (in shares) | shares	102,074	365,104	239,822
Component held by ESOP	$ 1,963	$ 7,151	$ 4,088
Shares returned to Treasury Stock (in shares) | shares	49,895	230,358	107,008
Proceeds from the sales of trading securities	$ 514	$ 4,629	$ 3,648
Tax benefit from market valuation adjustment on distribution of BMP ESOP shares	619	1,454	717
Defined contribution costs recognized	$ 59	$ 336	$ 744