BASIS OF PRESENTATION (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 01, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit loss		$ 119,937	$ 63,850	$ 119,937	$ 63,850	$ 97,350	$ 70,395	$ 62,639	$ 61,963
Retained earnings		723,067		723,067			702,502
Income tax expense (benefit)		7,417	$ 13,584	13,326	$ 21,894
Off-balance, credit loss liability		17,392		17,392		$ 15,468	248
Allowance for Credit Losses		$ 62		$ 62			0
Threshold period past due, nonperforming status of loans and leases				90 days
Impact of ASU 2016-13 adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit loss							12,071
Retained earnings	$ 14,900
Income tax expense (benefit)	5,000
Off-balance, credit loss liability							$ 13,604
Allowance for Credit Losses	158
Impact of ASU 2016-13 adoption | Held-to-maturity Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	118
Income tax expense (benefit)	40
Impact of ASU 2016-13 adoption | Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit loss	12,100
Retained earnings	4,600
Income tax expense (benefit)	1,500
Impact of ASU 2016-13 adoption | Loans | Financial Asset Acquired with Credit Deterioration
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit loss	6,000
Impact of ASU 2016-13 adoption | Unfunded Loan Commitment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	10,200
Income tax expense (benefit)	3,400
Off-balance, credit loss liability	$ 13,600