LOANS - Categorized by Class and Internally Assigned Risk Grades (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Loans by class categorized by internally assigned risk grades
Total loans	$ 3,500,968	$ 3,268,772
Pass
Loans by class categorized by internally assigned risk grades
Total loans	3,418,420	3,180,905
Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	42,773	43,186
Substandard
Loans by class categorized by internally assigned risk grades
Total loans	39,775	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	1,519,807	1,373,556
Commercial Real Estate | Mortgage loans | Owner occupied
Loans by class categorized by internally assigned risk grades
Total loans	529,483	510,398
Commercial Real Estate | Mortgage loans | Owner occupied | Pass
Loans by class categorized by internally assigned risk grades
Total loans	507,851	480,503
Commercial Real Estate | Mortgage loans | Owner occupied | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	20,395	12,045
Commercial Real Estate | Mortgage loans | Owner occupied | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	1,237	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	990,324	863,158
Commercial Real Estate | Mortgage loans | Non-owner occupied | Pass
Loans by class categorized by internally assigned risk grades
Total loans	977,896	858,069
Commercial Real Estate | Mortgage loans | Non-owner occupied | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	0	2,188
Commercial Real Estate | Mortgage loans | Non-owner occupied | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	12,428	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	673,909	585,827
Multi-family | Mortgage loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans	673,501	585,409
Multi-family | Mortgage loans | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	408	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	497,842	519,763
Residential real estate mortgage loans | Mortgage loans | Residential mortgage
Loans by class categorized by internally assigned risk grades
Total loans	428,954	448,515
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | Pass
Loans by class categorized by internally assigned risk grades
Total loans	418,648	438,891
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	8,213	8,510
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	2,093	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	68,888	71,248
Residential real estate mortgage loans | Mortgage loans | Home equity | Pass
Loans by class categorized by internally assigned risk grades
Total loans	67,435	68,480
Residential real estate mortgage loans | Mortgage loans | Home equity | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	674	1,594
Residential real estate mortgage loans | Mortgage loans | Home equity | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	779	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	667,949	645,724
Commercial, industrial and agricultural loans | Secured
Loans by class categorized by internally assigned risk grades
Total loans	160,808	168,540
Commercial, industrial and agricultural loans | Secured | Pass
Loans by class categorized by internally assigned risk grades
Total loans	149,772	147,474
Commercial, industrial and agricultural loans | Secured | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	1,227	5,536
Commercial, industrial and agricultural loans | Secured | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	9,809	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	507,141	477,184
Commercial, industrial and agricultural loans | Unsecured | Pass
Loans by class categorized by internally assigned risk grades
Total loans	483,037	458,526
Commercial, industrial and agricultural loans | Unsecured | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	11,852	12,886
Commercial, industrial and agricultural loans | Unsecured | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	12,252	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	116,463	123,393
Real estate construction and land loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans	116,047	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	416	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	24,998	20,509
Installment/consumer loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans	24,233	20,464
Installment/consumer loans | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans	4	9
Installment/consumer loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans	761	36
Installment/consumer loans | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans	$ 0	$ 0