REGULATORY CAPITAL REQUIREMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Company (consolidated) [Member]
Total capital (to risk weighted assets):
Actual	$ 824,265	$ 747,372
Actual Ratio	13.60%	13.36%
Capital Required for Capital Adequacy	$ 484,942	$ 447,664
For Capital Adequacy Purposes Ratio	8.00%	8.00%
Common Equity Tier One Capital	$ 656,080	$ 584,378
Common Equity tier One Capital to Risk Weighted Assets	10.82%	10.44%
Common Equity Tier One Capital Required for Capital Adequacy	$ 272,780	$ 251,811
Common Equity Tier One Capital for Capitalized Adequacy to Risk Weighted Assets	4.50%	4.50%
Tier 1 capital (to risk weighted assets):
Actual	$ 727,070	$ 655,154
Actual Ratio	11.99%	11.71%
For Capital Adequacy Purposes	$ 363,706	$ 335,748
For Capital Adequacy Purposes Ratio	6.00%	6.00%
Tier 1 capital (to average assets):
Actual	$ 727,070	$ 655,154
Actual Ratio	9.77%	9.33%
For Capital Adequacy Purposes	$ 297,748	$ 280,889
For Capital Adequacy Purposes Ratio	4.00%	4.00%
Bank [Member]
Total capital (to risk weighted assets):
Actual	$ 788,320	$ 718,197
Actual Ratio	13.01%	12.84%
Capital Required for Capital Adequacy	$ 484,834	$ 447,334
For Capital Adequacy Purposes Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions	$ 606,042	$ 559,167
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%	10.00%
Common Equity Tier One Capital	$ 725,760	$ 660,979
Common Equity tier One Capital to Risk Weighted Assets	11.98%	11.82%
Common Equity Tier One Capital Required for Capital Adequacy	$ 272,719	$ 251,625
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	$ 393,927	$ 363,459
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	$ 725,760	$ 660,979
Actual Ratio	11.98%	11.82%
For Capital Adequacy Purposes	$ 363,625	$ 335,500
For Capital Adequacy Purposes Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions	$ 484,834	$ 447,334
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00%	8.00%
Tier 1 capital (to average assets):
Actual	$ 725,760	$ 660,979
Actual Ratio	9.76%	9.42%
For Capital Adequacy Purposes	$ 297,589	$ 280,653
For Capital Adequacy Purposes Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Correction Action Provisions	$ 371,986	$ 350,816
To Be Well Capitalized Under Prompt Correction Action Provisions Ratio	5.00%	5.00%