REGULATORY MATTERS (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Tier 1 Leverage ratio [Abstract]
Required capital conservation ratio	2.50%	2.50%
Tier 1 Leverage ratio, actual amount	$ 1,331,368	$ 1,314,864
Tier 1 Leverage ratio, actual ratio	9.09	10.16
Tier 1 leverage ratio for capital adequacy purposes, amount	$ 585,594	$ 517,736
Tier 1 leverage ratio for capital adequacy purposes, ratio	4.00	4.00
Tier 1 leverage capital to be well-capitalized under prompt corrective action, amount	$ 731,993	$ 647,169
Tier 1 leverage capital to be well-capitalized under prompt corrective action, ratio	5.00	5.00
Tier 1 risk-based capital [Abstract]
Tier 1 risk-based capital, actual amount	$ 1,331,368	$ 1,314,864
Tier 1 risk-based capital, actual ratio	18.60	18.99
Tier 1 risk-based capital for capital adequacy purposes, amount	$ 429,559	$ 415,472
Tier 1 risk-based capital for capital adequacy purposes, ratio	6.00	6.00
Tier 1 risk-based capital for capital adequacy purposes plus capital conservation buffer, amount	$ 608,542	$ 588,585
Tier 1 risk-based capital for capital adequacy purposes plus capital conservation buffer, ratio	8.50%	8.50%
Tier 1 risk based capital to be well-capitalized under prompt corrective action, amount	$ 572,746	$ 553,962
Tier 1 risk-based capital to be well-capitalized under prompt corrective action, ratio	8.00	8.00
Total risk-based capital [Abstract]
Total risk-based capital, actual amount	$ 1,380,458	$ 1,375,704
Total risk-based capital, actual ratio	19.28	19.87
Total risk-based capital for capital adequacy purposes, amount	$ 572,746	$ 553,962
Total risk-based capita for capital adequacy purposes, ratio	8.00	8.00
Total risk-based capital for capital adequacy purposes plus capital conservation buffer, amount	$ 751,729	$ 727,075
Total risk-based capita for capital adequacy purposes plus capital conservation buffer, ratio	10.50%	10.50%
Total risk based capital to be well-capitalized under prompt corrective action, amount	$ 715,932	$ 692,453
Total risk based capital to be well-capitalized under prompt corrective action, ratio	10.00	10.00
Common equity Tier 1 capital [Abstract]
Common equity Tier 1 capital, actual amount	$ 1,331,259	$ 1,239,754
Common equity Tier 1 capital, actual ratio	18.60	17.90
Common equity Tier 1 capital for capital adequacy purposes, amount	$ 322,169	$ 311,604
Common equity Tier 1 capital for capital adequacy purposes, ratio	4.50%	4.50%
Common equity Tier 1 capital for capital adequacy purposes plus capital conservation buffer, amount	$ 501,152	$ 484,717
Common equity Tier 1 capital for capital adequacy purposes plus capital conservation buffer, ratio	7.00%	7.00%
Common equity Tier 1 capital to be well-capitalized under prompt corrective action, amount	$ 465,356	$ 450,094
Common equity Tier 1 capital to be well-capitalized under prompt corrective action, ratio	6.50%	6.50%
Community Bank, N.A. [Member]
Tier 1 Leverage ratio [Abstract]
Tier 1 Leverage ratio, actual amount	$ 1,058,091	$ 1,028,285
Tier 1 Leverage ratio, actual ratio	7.26	7.98
Tier 1 leverage ratio for capital adequacy purposes, amount	$ 582,631	$ 515,552
Tier 1 leverage ratio for capital adequacy purposes, ratio	4.00	4.00
Tier 1 leverage capital to be well-capitalized under prompt corrective action, amount	$ 728,289	$ 644,440
Tier 1 leverage capital to be well-capitalized under prompt corrective action, ratio	5.00	5.00
Tier 1 risk-based capital [Abstract]
Tier 1 risk-based capital, actual amount	$ 1,058,091	$ 1,028,285
Tier 1 risk-based capital, actual ratio	14.92	14.98
Tier 1 risk-based capital for capital adequacy purposes, amount	$ 425,393	$ 411,880
Tier 1 risk-based capital for capital adequacy purposes, ratio	6.00	6.00
Tier 1 risk-based capital for capital adequacy purposes plus capital conservation buffer, amount	$ 602,640	$ 583,497
Tier 1 risk-based capital for capital adequacy purposes plus capital conservation buffer, ratio	8.50%	8.50%
Tier 1 risk based capital to be well-capitalized under prompt corrective action, amount	$ 567,190	$ 549,174
Tier 1 risk-based capital to be well-capitalized under prompt corrective action, ratio	8.00	8.00
Total risk-based capital [Abstract]
Total risk-based capital, actual amount	$ 1,107,181	$ 1,089,125
Total risk-based capital, actual ratio	15.62	15.87
Total risk-based capital for capital adequacy purposes, amount	$ 567,190	$ 549,174
Total risk-based capita for capital adequacy purposes, ratio	8.00	8.00
Total risk-based capital for capital adequacy purposes plus capital conservation buffer, amount	$ 744,437	$ 720,791
Total risk-based capita for capital adequacy purposes plus capital conservation buffer, ratio	10.50%	10.50%
Total risk based capital to be well-capitalized under prompt corrective action, amount	$ 708,988	$ 686,467
Total risk based capital to be well-capitalized under prompt corrective action, ratio	10.00	10.00
Common equity Tier 1 capital [Abstract]
Common equity Tier 1 capital, actual amount	$ 1,057,982	$ 1,028,175
Common equity Tier 1 capital, actual ratio	14.92	14.98
Common equity Tier 1 capital for capital adequacy purposes, amount	$ 319,045	$ 308,910
Common equity Tier 1 capital for capital adequacy purposes, ratio	4.50%	4.50%
Common equity Tier 1 capital for capital adequacy purposes plus capital conservation buffer, amount	$ 496,292	$ 480,527
Common equity Tier 1 capital for capital adequacy purposes plus capital conservation buffer, ratio	7.00%	7.00%
Common equity Tier 1 capital to be well-capitalized under prompt corrective action, amount	$ 460,842	$ 446,204
Common equity Tier 1 capital to be well-capitalized under prompt corrective action, ratio	6.50%	6.50%