LOANS (Loans receivable) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 10,177,385	$ 9,954,572
Allowance for credit losses	(100,522)	(110,088)	$ (130,172)	$ (131,606)
Loans receivable, net	10,076,863	9,844,484
Accrued interest receivable	33,000	35,300
Commercial and industrial \| Commercial and industrial
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,814,513	2,645,085
Allowance for credit losses	(25,800)	(27,738)	(36,095)	(38,818)
Commercial and industrial \| Paycheck Protection Program ("PPP")
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	74,065	199,883
Allowance for credit losses	0	0	0	0
Commercial and industrial \| Owner occupied commercial real estate
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,266,076	2,240,334
Allowance for credit losses	(17,975)	(19,214)	(19,416)	(20,001)
Commercial and industrial \| Non-owner occupied commercial real estate
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,161,761	2,010,591
Allowance for credit losses	(16,013)	(17,908)	(24,694)	(20,873)
Commercial and industrial \| Real estate construction
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	842,483	856,119
Allowance for credit losses	(21,397)	(22,538)	(19,931)	(20,080)
Agricultural and agricultural real estate
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	766,443	753,753
Allowance for credit losses	(2,667)	(5,213)	(7,111)	(7,129)
Residential real estate
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	825,242	829,283
Allowance for credit losses	(7,875)	(8,427)	(11,012)	(11,935)
Consumer
Loans and Leases [Line Items]
Financing Receivable, before Allowance for Credit Loss	426,802	419,524
Allowance for credit losses	$ (8,795)	$ (9,050)	$ (11,913)	$ (12,770)

Loans and Leases [Line Items]

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Amount, before allowance for credit loss, of accrued interest on financing receivable.

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