LOANS - Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	$ 329	$ 308
Nonaccrual Including 90 Days or More Past Due	5,509	2,808
Total Past Due and Nonaccrual	9,220	7,516
Current	3,413,362	3,261,256
Total Loans	3,422,582	3,268,772
30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	1,651	3,780
60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	1,731	620
Commercial Real Estate | Mortgage loans
Past Due and Nonaccrual Loans
Total Loans	1,436,221	1,373,556
Commercial Real Estate | Mortgage loans | Owner occupied
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	573	253
Total Past Due and Nonaccrual	1,214	780
Current	524,115	509,618
Total Loans	525,329	510,398
Commercial Real Estate | Mortgage loans | Owner occupied | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	333
Commercial Real Estate | Mortgage loans | Owner occupied | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	641	194
Commercial Real Estate | Mortgage loans | Non-owner occupied
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	1,376	885
Total Past Due and Nonaccrual	1,376	885
Current	909,516	862,273
Total Loans	910,892	863,158
Commercial Real Estate | Mortgage loans | Non-owner occupied | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Commercial Real Estate | Mortgage loans | Non-owner occupied | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Multi-family | Mortgage loans
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	0	0
Total Past Due and Nonaccrual	0	0
Current	631,146	585,827
Total Loans	631,146	585,827
Multi-family | Mortgage loans | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Multi-family | Mortgage loans | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Residential real estate mortgage loans | Mortgage loans
Past Due and Nonaccrual Loans
Total Loans	503,354	519,763
Residential real estate mortgage loans | Mortgage loans | Residential mortgage
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	2,138	199
Total Past Due and Nonaccrual	2,302	1,321
Current	433,084	447,194
Total Loans	435,386	448,515
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	164	892
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	230
Residential real estate mortgage loans | Mortgage loans | Home equity
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	329	308
Nonaccrual Including 90 Days or More Past Due	370	624
Total Past Due and Nonaccrual	1,050	1,965
Current	66,918	69,283
Total Loans	67,968	71,248
Residential real estate mortgage loans | Mortgage loans | Home equity | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	300	1,033
Residential real estate mortgage loans | Mortgage loans | Home equity | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	51	0
Commercial, industrial and agricultural loans
Past Due and Nonaccrual Loans
Total Loans	675,168	645,724
Commercial, industrial and agricultural loans | Secured
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	218	174
Total Past Due and Nonaccrual	1,384	700
Current	163,566	167,840
Total Loans	164,950	168,540
Commercial, industrial and agricultural loans | Secured | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	835	330
Commercial, industrial and agricultural loans | Secured | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	331	196
Commercial, industrial and agricultural loans | Unsecured
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	683	621
Total Past Due and Nonaccrual	1,705	1,729
Current	508,513	475,455
Total Loans	510,218	477,184
Commercial, industrial and agricultural loans | Unsecured | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	314	1,108
Commercial, industrial and agricultural loans | Unsecured | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	708	0
Real estate construction and land loans
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	129	0
Total Past Due and Nonaccrual	129	0
Current	150,739	123,393
Total Loans	150,868	123,393
Real estate construction and land loans | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Real estate construction and land loans | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Installment/consumer loans
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	22	52
Total Past Due and Nonaccrual	60	136
Current	25,765	20,373
Total Loans	25,825	20,509
Installment/consumer loans | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	38	84
Installment/consumer loans | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	$ 0	$ 0