BORROWINGS (Maturities of Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	$ 14,063
2016	0
2017	0
2018	0
2019	0
Thereafter	112,888
Long-term Debt, Gross	126,951
Long-term Debt [Member] \| Long-term Debt [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	14,063
2016	0
2017	0
2018	0
2019	0
Thereafter	0
Total		$ 14,063
Junior Subordinated Debentures [Member] \| Capital Trust V Preferred Securities Due in 2037 [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	0
2016	0
2017	0
2018	0
2019	0
Thereafter	51,547
Total	51,547
Junior Subordinated Debentures [Member] \| Central Bancorp Capital Trust I Securities Due in 2034 [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	0
2016	0
2017	0
2018	0
2019	0
Thereafter	5,258
Total	5,258
Junior Subordinated Debentures [Member] \| Central Bancorp Capital Trust II Securities Due in 2037 [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	0
2016	0
2017	0
2018	0
2019	0
Thereafter	6,083
Total	6,083
Subordinated Debentures [Member] \| Subordinated Debentures Due August 27, 2018 [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	0
2016	0
2017	0
2018	0
2019	0
Subordinated Debentures [Member] \| Subordinated note due 2029 [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Thereafter	50,000
Total	$ 50,000

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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