FAIR VALUE - CARRYING AMOUNTS AND FV OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Assets:
Available-for-sale debt securities	$ 543,859	$ 471,355
Held-to-maturity debt securities	59,725	63,156
Equity securities with readily determinable fair value	2,807	3,188
Mortgage loans held for sale, at fair value	39,384	19,224	$ 11,313	$ 8,971
Consumer loans held for sale, at fair value	3,431	598
Consumer loans held for sale, at the lower of cost or fair value	12,089	11,646	$ 12,864	$ 12,838
Carrying Value
Assets:
Cash and cash equivalents	316,263	385,303
Available-for-sale debt securities	543,859	471,355
Held-to-maturity debt securities	61,664	62,531
Equity securities with readily determinable fair value	2,807	3,188
Mortgage loans held for sale, at fair value	39,384	19,224
Consumer loans held for sale, at fair value	3,431	598
Consumer loans held for sale, at the lower of cost or fair value	12,089	11,646
Loans, net	4,445,168	4,389,800
Federal Home Loan Bank stock	38,900	30,831
Accrued interest receivable	12,037	12,937
Rate lock loan commitments	4,568	789
Interest rate swap agreements	14,013	5,062
Liabilities:
Securities sold under agreements to repurchase and other short-term borrowings	126,080	167,617
Federal Home Loan Bank advances	572,500	750,000
Subordinated note	41,240	41,240
Accrued interest payable	3,437	2,802
Mandatory forward contracts	2,826	131
Interest rate swap agreements	14,249	5,166
Carrying Value | Non Interest Bearing Deposits
Liabilities:
Deposit liabilities, fair value	1,300,891	1,033,379
Carrying Value | Transaction deposits
Liabilities:
Deposit liabilities, fair value	2,033,829	2,018,687
Carrying Value | Time deposits.
Liabilities:
Deposit liabilities, fair value	736,737	733,942
Total Fair Value
Assets:
Cash and cash equivalents	316,263	385,303
Available-for-sale debt securities	543,859	471,355
Held-to-maturity debt securities	59,725	63,156
Equity securities with readily determinable fair value	2,807	3,188
Mortgage loans held for sale, at fair value	39,384	19,224
Consumer loans held for sale, at fair value	3,431	598
Consumer loans held for sale, at the lower of cost or fair value	12,089	11,646
Loans, net	4,425,308	4,381,396
Accrued interest receivable	12,037	12,937
Rate lock loan commitments	4,568	789
Interest rate swap agreements	14,013	5,062
Liabilities:
Securities sold under agreements to repurchase and other short-term borrowings	126,080	167,617
Federal Home Loan Bank advances	575,135	749,667
Subordinated note	34,571	32,587
Accrued interest payable	3,437	2,802
Mandatory forward contracts	2,826	131
Interest rate swap agreements	14,249	5,166
Total Fair Value | Non Interest Bearing Deposits
Liabilities:
Deposit liabilities, fair value	1,300,891	1,033,379
Total Fair Value | Transaction deposits
Liabilities:
Deposit liabilities, fair value	2,033,829	2,018,687
Total Fair Value | Time deposits.
Liabilities:
Deposit liabilities, fair value	748,977	737,733
Total Fair Value | Fair Value, Inputs, Level 1
Assets:
Cash and cash equivalents	316,263	385,303
Equity securities with readily determinable fair value	2,513	2,474
Total Fair Value | Fair Value, Inputs, Level 2
Assets:
Available-for-sale debt securities	536,510	463,860
Held-to-maturity debt securities	59,725	63,156
Equity securities with readily determinable fair value	294	714
Mortgage loans held for sale, at fair value	39,384	19,224
Accrued interest receivable	12,037	12,937
Rate lock loan commitments	4,568	789
Interest rate swap agreements	14,013	5,062
Liabilities:
Securities sold under agreements to repurchase and other short-term borrowings	126,080	167,617
Federal Home Loan Bank advances	575,135	749,667
Subordinated note	34,571	32,587
Accrued interest payable	3,437	2,802
Mandatory forward contracts	2,826	131
Interest rate swap agreements	14,249	5,166
Total Fair Value | Fair Value, Inputs, Level 2 | Non Interest Bearing Deposits
Liabilities:
Deposit liabilities, fair value	1,300,891	1,033,379
Total Fair Value | Fair Value, Inputs, Level 2 | Transaction deposits
Liabilities:
Deposit liabilities, fair value	2,033,829	2,018,687
Total Fair Value | Fair Value, Inputs, Level 2 | Time deposits.
Liabilities:
Deposit liabilities, fair value	748,977	737,733
Total Fair Value | Fair Value, Inputs, Level 3
Assets:
Available-for-sale debt securities	7,349	7,495
Consumer loans held for sale, at fair value	3,431	598
Consumer loans held for sale, at the lower of cost or fair value	12,089	11,646
Loans, net	$ 4,425,308	$ 4,381,396