REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Other noninterest income - ASC 606									$ 8,696	$ 4,432	$ 4,569
Total noninterest income in scope of ASC 606									80,116	68,709	64,259
Total noninterest income out of scope of ASC 606									35,178	19,796	18,735
Noninterest Income	$ 33,297	$ 31,816	$ 28,648	$ 21,533	$ 23,491	$ 23,264	$ 21,887	$ 19,863	115,294	88,505	82,994
Deposit Account [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									20,040	18,327	17,822
Credit Card, Merchant Discount [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									18,262	15,433	13,899
ATM Charge [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									3,224	2,961	2,938
Investment Advisory, Management and Administrative Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									25,940	23,441	21,644
Investment Advisory, Retail Investment and Insurance Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									2,779	2,714	2,158
Merchant Processing [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 1,175	$ 1,401	$ 1,229