REGULATORY CAPITAL REQUIREMENTS (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Company (consolidated) [Member]
Total capital (to risk weighted assets):
Actual	$ 1,374,349	$ 1,352,341
Actual Ratio	0.1513	0.1483
Capital Required for Capital Adequacy	$ 726,482	$ 729,291
For Capital Adequacy Purposes Ratio	0.080	0.080
Common Equity Tier One Capital	$ 1,150,177	$ 1,171,963
Common Equity tier One Capital to Risk Weighted Assets	12.67%	12.86%
Common Equity Tier One Capital Required for Capital Adequacy	$ 408,646	$ 410,226
Common Equity Tier One Capital for Capitalized Adequacy to Risk Weighted Assets	4.50%	4.50%
Tier 1 capital (to risk weighted assets):
Actual	$ 1,211,177	$ 1,232,963
Actual Ratio	0.1334	0.1353
For Capital Adequacy Purposes	$ 544,861	$ 546,969
For Capital Adequacy Purposes Ratio	0.060	0.060
Tier 1 capital (to average assets):
Actual	$ 1,211,177	$ 1,232,963
Actual Ratio	0.0956	0.1128
For Capital Adequacy Purposes	$ 506,805	$ 437,271
For Capital Adequacy Purposes Ratio	0.040	0.040
Bank [Member]
Total capital (to risk weighted assets):
Actual	$ 1,320,056	$ 1,275,611
Actual Ratio	0.1454	0.1400
Capital Required for Capital Adequacy	$ 726,313	$ 728,868
For Capital Adequacy Purposes Ratio	0.080	0.080
To Be Well Capitalized Under Prompt Corrective Action Provisions	$ 907,892	$ 911,085
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	0.100	0.100
Common Equity Tier One Capital	$ 1,206,566	$ 1,205,740
Common Equity tier One Capital to Risk Weighted Assets	13.29%	13.23%
Common Equity Tier One Capital Required for Capital Adequacy	$ 408,551	$ 409,988
Common Equity Tier One Capital for Capitalized Adequacy to Risk Weighted Assets	4.50%	4.50%
Common Equity Tier 1 Capital to be Well Capitalized	$ 590,130	$ 592,205
Common Equity Tier One Capital to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Tier 1 capital (to risk weighted assets):
Actual	$ 1,206,566	$ 1,205,740
Actual Ratio	0.1329	0.1323
For Capital Adequacy Purposes	$ 544,735	$ 546,651
For Capital Adequacy Purposes Ratio	0.060	0.060
To Be Well Capitalized Under Prompt Corrective Action Provisions	$ 726,313	$ 728,868
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	0.080	0.080
Tier 1 capital (to average assets):
Actual	$ 1,206,566	$ 1,205,740
Actual Ratio	0.0954	0.1106
For Capital Adequacy Purposes	$ 505,747	$ 435,886
For Capital Adequacy Purposes Ratio	0.040	0.040
To Be Well Capitalized Under Prompt Correction Action Provisions	$ 632,184	$ 544,857
To Be Well Capitalized Under Prompt Correction Action Provisions Ratio	0.050	0.050