LOANS AND ALLOWANCE FOR LOAN LOSSES - PPP Loans and CARES Act Deferrals (Details) $ in Thousands	Dec. 31, 2020 USD ($) loan	Dec. 31, 2019 USD ($)
Financing Receivable, Impaired [Line Items]
Loan balance	$ 1,454,801	$ 1,374,235
Commercial
Financing Receivable, Impaired [Line Items]
Loan balance	1,141,114	1,063,828
Loans approved for modification	34,700
Consumer
Financing Receivable, Impaired [Line Items]
Loan balance	3,156	$ 3,697
Loans approved for modification	$ 13,500
SBA PPP
Financing Receivable, Impaired [Line Items]
Number of loans | loan	455
Original balance of loans	$ 92,800
Loan balance	$ 82,000