LOANS - Categorized by Class and Internally Assigned Risk Grades (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans by class categorized by internally assigned risk grades
Total loans	$ 3,383,714	$ 3,268,772
Pass
Loans by class categorized by internally assigned risk grades
Total loans	3,292,817	3,180,905
Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	47,305	43,186
Substandard
Loans by class categorized by internally assigned risk grades
Total loans	43,592	44,681
Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Commercial Real Estate | Mortgage loans
Loans by class categorized by internally assigned risk grades
Total loans	1,402,633	1,373,556
Commercial Real Estate | Mortgage loans | Owner occupied
Loans by class categorized by internally assigned risk grades
Total loans	542,836	510,398
Commercial Real Estate | Mortgage loans | Owner occupied | Pass
Loans by class categorized by internally assigned risk grades
Total loans	513,116	480,503
Commercial Real Estate | Mortgage loans | Owner occupied | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	11,652	12,045
Commercial Real Estate | Mortgage loans | Owner occupied | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	18,068	17,850
Commercial Real Estate | Mortgage loans | Owner occupied | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Commercial Real Estate | Mortgage loans | Non-owner occupied
Loans by class categorized by internally assigned risk grades
Total loans	859,797	863,158
Commercial Real Estate | Mortgage loans | Non-owner occupied | Pass
Loans by class categorized by internally assigned risk grades
Total loans	845,486	858,069
Commercial Real Estate | Mortgage loans | Non-owner occupied | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	10,564	2,188
Commercial Real Estate | Mortgage loans | Non-owner occupied | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	3,747	2,901
Commercial Real Estate | Mortgage loans | Non-owner occupied | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Multi-family | Mortgage loans
Loans by class categorized by internally assigned risk grades
Total loans	624,114	585,827
Multi-family | Mortgage loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans	623,699	585,409
Multi-family | Mortgage loans | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	415	418
Multi-family | Mortgage loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Multi-family | Mortgage loans | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Residential real estate mortgage loans | Mortgage loans
Loans by class categorized by internally assigned risk grades
Total loans	515,173	519,763
Residential real estate mortgage loans | Mortgage loans | Residential mortgage
Loans by class categorized by internally assigned risk grades
Total loans	446,549	448,515
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | Pass
Loans by class categorized by internally assigned risk grades
Total loans	436,967	438,891
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	8,278	8,510
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	1,304	1,114
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Residential real estate mortgage loans | Mortgage loans | Home equity
Loans by class categorized by internally assigned risk grades
Total loans	68,624	71,248
Residential real estate mortgage loans | Mortgage loans | Home equity | Pass
Loans by class categorized by internally assigned risk grades
Total loans	66,569	68,480
Residential real estate mortgage loans | Mortgage loans | Home equity | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	992	1,594
Residential real estate mortgage loans | Mortgage loans | Home equity | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	1,063	1,174
Residential real estate mortgage loans | Mortgage loans | Home equity | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Commercial, industrial and agricultural loans
Loans by class categorized by internally assigned risk grades
Total loans	671,897	645,724
Commercial, industrial and agricultural loans | Secured
Loans by class categorized by internally assigned risk grades
Total loans	163,638	168,540
Commercial, industrial and agricultural loans | Secured | Pass
Loans by class categorized by internally assigned risk grades
Total loans	151,751	147,474
Commercial, industrial and agricultural loans | Secured | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	2,762	5,536
Commercial, industrial and agricultural loans | Secured | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	9,125	15,530
Commercial, industrial and agricultural loans | Secured | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Commercial, industrial and agricultural loans | Unsecured
Loans by class categorized by internally assigned risk grades
Total loans	508,259	477,184
Commercial, industrial and agricultural loans | Unsecured | Pass
Loans by class categorized by internally assigned risk grades
Total loans	486,419	458,526
Commercial, industrial and agricultural loans | Unsecured | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	11,885	12,886
Commercial, industrial and agricultural loans | Unsecured | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	9,955	5,772
Commercial, industrial and agricultural loans | Unsecured | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Real estate construction and land loans
Loans by class categorized by internally assigned risk grades
Total loans	147,116	123,393
Real estate construction and land loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans	146,816	123,089
Real estate construction and land loans | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Real estate construction and land loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	300	304
Real estate construction and land loans | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	0	0
Installment/consumer loans
Loans by class categorized by internally assigned risk grades
Total loans	22,781	20,509
Installment/consumer loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans	21,994	20,464
Installment/consumer loans | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	757	9
Installment/consumer loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	30	36
Installment/consumer loans | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	$ 0	$ 0