LOANS (Schedule of Balances by Portfolio Class, Based on Impairment Method) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Total Loans Individually Evaluated for Impairment	$ 31,345		$ 23,065
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	743		522
Total Loans Collectively Evaluated for Impairment	3,763,885		3,679,467
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	36,550		35,918
Total Loans	3,795,230		3,702,532
Total Ending ALLL	37,293	$ 38,066	36,440	$ 35,915	$ 35,751	$ 32,208
Residential Portfolio Segment [Member] | Primary Residential Mortgages [Member]
Total Loans Individually Evaluated for Impairment	9,103		9,802
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	358		482
Total Loans Collectively Evaluated for Impairment	583,180		595,767
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	3,774		3,603
Total Loans	592,283		605,569
Total Ending ALLL	4,132	4,382	4,085	4,344	4,223	3,666
Residential Portfolio Segment [Member] | Home Equity Lines of Credit [Member]
Total Loans Individually Evaluated for Impairment	266		27
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	0
Total Loans Collectively Evaluated for Impairment	59,663		67,470
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	197		221
Total Loans	59,929		67,497
Total Ending ALLL	197	190	221	229	211	233
Residential Portfolio Segment [Member] | Multifamily Property [Member]
Total Loans Individually Evaluated for Impairment	1,269
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	385
Total Loans Collectively Evaluated for Impairment	1,284,547		1,388,958
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	7,270		10,007
Total Loans	1,285,816		1,388,958
Total Ending ALLL	7,655	8,259	10,007	11,246	11,606	11,192
Residential Portfolio Segment [Member] | Junior Lien [Member]
Total Loans Individually Evaluated for Impairment	44		52
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	0
Total Loans Collectively Evaluated for Impairment	7,487		7,021
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	16		12
Total Loans	7,531		7,073
Total Ending ALLL	16	17	12	13	14	16
Commercial Real Estate Portfolio Segment [Member] | Owner Occupied Property [Member]
Total Loans Individually Evaluated for Impairment	1,934		2,503
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	0
Total Loans Collectively Evaluated for Impairment	247,236		250,989
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	2,387		2,385
Total Loans	249,170		253,492
Total Ending ALLL	2,387	2,525	2,385	2,270	2,147	1,774
Commercial Real Estate Portfolio Segment [Member] | Investment Property [Member]
Total Loans Individually Evaluated for Impairment	18,729		10,681
Ending ALLL Attributable to Loans Individually Evaluated for Impairment			40
Total Loans Collectively Evaluated for Impairment	883,091		863,417
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	12,791		11,893
Total Loans	901,820		874,098
Total Ending ALLL	12,791	13,659	11,933	11,957	11,727	10,909
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Total Loans Collectively Evaluated for Impairment	88		92
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	1		1
Total Loans	88		92
Total Ending ALLL	1	1	1	1	1	9
Consumer and Other Loans [Member]
Total Loans Collectively Evaluated for Impairment	67,489		99,247
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	378		349
Total Loans	67,489		99,247
Total Ending ALLL	378	364	349	343	309	243
Commercial and Industrial Sector [Member] | Commercial Portfolio Segment [Member]
Total Loans Individually Evaluated for Impairment	0
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	0
Total Loans Collectively Evaluated for Impairment	479,763		316,294
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	8,185		6,563
Total Loans	479,763		316,294
Total Ending ALLL	8,185	7,356	6,563	5,235	5,333	4,164
Lease Financing [Member]
Total Loans Individually Evaluated for Impairment	0
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	0
Total Loans Collectively Evaluated for Impairment	151,189		90,052
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	1,549		884
Total Loans	151,189		90,052
Total Ending ALLL	1,549		884
Agricultural Sector [Member]
Total Loans Collectively Evaluated for Impairment	152		160
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	2
Total Loans	152		$ 160
Total Ending ALLL	$ 2	$ 2		$ 2	$ 2	$ 2