LOANS AND ALLOWANCE FOR CREDIT LOSSES - Loans Evaluated for Impairment (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Allowance for loan losses
Loans and Leases Receivable, Net Amount	$ 2,527,411	$ 2,543,803
Real Estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	13,566	13,693
Other
Allowance for loan losses
Loans and Leases Receivable, Net Amount	503	607
Commercial construction | Total commercial loans
Allowance for loan losses
Loans and Leases Receivable, Net Amount	117,464
Commercial construction | Total commercial loans | Real Estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount		259
Commercial real estate owner occupied | Total commercial real estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	233,847
Commercial real estate owner occupied | Total commercial real estate | Real Estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	1,576	3,441
Commercial real estate non-owner occupied | Total commercial real estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	733,507
Commercial real estate non-owner occupied | Total commercial real estate | Real Estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	930	383
Tax exempt
Allowance for loan losses
Loans and Leases Receivable, Net Amount	46,541
Commercial and industrial | Total commercial and industrial
Allowance for loan losses
Loans and Leases Receivable, Net Amount	376,395
Commercial and industrial | Total commercial and industrial | Real Estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	564	625
Commercial and industrial | Total commercial and industrial | Other
Allowance for loan losses
Loans and Leases Receivable, Net Amount	503	607
Residential mortgages | Total residential real estate | Real Estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	9,142	7,432
Home equity | Real Estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	1,344	1,493
Consumer other | Total consumer | Real Estate
Allowance for loan losses
Loans and Leases Receivable, Net Amount	$ 10	$ 60