LOANS - Risk Rating (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) grade	Dec. 31, 2019 USD ($)
Loans by risk rating
Number of grades utilized in internal loan rating system | grade	10
Total loans	$ 3,183,870	$ 3,171,558
Commercial
Loans by risk rating
Total loans	1,691,086	1,630,112
Commercial real estate | Commercial
Loans by risk rating
Total loans	1,212,534	1,169,923
Commercial real estate | Commercial | Loans rated 1 - 6, pass
Loans by risk rating
Total loans	1,207,443	1,163,342
Commercial real estate | Commercial | Loans rated 7, special mention
Loans by risk rating
Total loans	259	4,539
Commercial real estate | Commercial | Loans rated 8, substandard
Loans by risk rating
Total loans	524	530
Commercial real estate | Commercial | Loans rated 9, doubtful
Loans by risk rating
Total loans	3,208
Commercial real estate | Commercial | Loans not rated
Loans by risk rating
Total loans	1,100	1,512
Commercial construction | Commercial
Loans by risk rating
Total loans	160,993	153,907
Commercial construction | Commercial | Loans rated 1 - 6, pass
Loans by risk rating
Total loans	135,422	127,962
Commercial construction | Commercial | Loans rated 7, special mention
Loans by risk rating
Total loans	14,632	14,701
Commercial construction | Commercial | Loans rated 8, substandard
Loans by risk rating
Total loans	10,939	11,244
Commercial and industrial | Commercial
Loans by risk rating
Total loans	317,559	306,282
Commercial and industrial | Commercial | Loans rated 1 - 6, pass
Loans by risk rating
Total loans	306,142	294,507
Commercial and industrial | Commercial | Loans rated 7, special mention
Loans by risk rating
Total loans	6,460	6,117
Commercial and industrial | Commercial | Loans rated 8, substandard
Loans by risk rating
Total loans	2,699	3,223
Commercial and industrial | Commercial | Loans rated 9, doubtful
Loans by risk rating
Total loans	$ 2,258	$ 2,435