REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Other noninterest income - ASC 606									$ 4,235	$ 8,696	$ 4,432
Total noninterest income in scope of ASC 606									65,905	80,116	68,709
Total noninterest income out of scope of ASC 606									45,535	35,178	19,796
Noninterest Income	$ 27,468	$ 29,347	$ 28,190	$ 26,435	$ 33,297	$ 31,816	$ 28,648	$ 21,533	111,440	115,294	88,505
Deposit Account [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									15,121	20,040	18,327
Credit Card, Merchant Discount [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									12,564	18,262	15,433
ATM Charge [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									2,476	3,224	2,961
Investment Advisory, Management and Administrative Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									27,157	25,940	23,441
Investment Advisory, Retail Investment and Insurance Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									2,275	2,779	2,714
Merchant Processing [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									1,299	1,175	1,401
Credit Card Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 778	$ 0	$ 0