FAIR VALUE DISCLOSURES - Certain assets measured on a non recurring basis (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Impaired Loans
Total loans	$ 2,438,711	$ 2,286,766
Level 3 Inputs | Non-recurring basis
Impaired Loans
Total loans	10,530	2,698
Level 3 Inputs | Non-recurring basis | Commercial and industrial
Impaired Loans
Total loans		340
Level 3 Inputs | Non-recurring basis | Commercial real estate
Impaired Loans
Total loans	603	603
Level 3 Inputs | Non-recurring basis | 1-4 family residential
Impaired Loans
Total loans	1,722	$ 1,755
Level 3 Inputs | Non-recurring basis | Other
Impaired Loans
Total loans	$ 8,205