LOANS (Schedule of Balances by Portfolio Class, Based on Impairment Method) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Total Loans Individually Evaluated for Impairment	$ 26,546	$ 29,071
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	754	824
Total Loans Collectively Evaluated for Impairment	3,411,690	3,281,033
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	32,856	31,384
Total Loans	3,438,236	3,310,104
Total Ending ALLL	33,610	32,208	$ 27,321	$ 25,856
Residential Portfolio Segment [Member] | Junior Lien [Member]
Total Loans Individually Evaluated for Impairment	111	229
Total Loans Collectively Evaluated for Impairment	8,376	8,977
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	15	16
Total Loans	8,487	9,206
Total Ending ALLL	15	16	13	66
Consumer and Other [Member]
Total Loans Collectively Evaluated for Impairment	73,880	73,621
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	236	243
Total Loans	73,880	73,621
Total Ending ALLL	236	243	136	112
Primary Residential Mortgages [Member] | Residential Portfolio Segment [Member]
Total Loans Individually Evaluated for Impairment	13,556	15,814
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	475	456
Total Loans Collectively Evaluated for Impairment	588,880	542,156
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	3,453	3,210
Total Loans	602,436	557,970
Total Ending ALLL	3,928	3,666	2,503	2,297
Home Equity Lines of Credit [Member] | Residential Portfolio Segment [Member]
Total Loans Individually Evaluated for Impairment	53	53
Total Loans Collectively Evaluated for Impairment	68,002	65,630
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	231	233
Total Loans	68,055	65,683
Total Ending ALLL	231	233	133	86
Multifamily Property [Member] | Residential Portfolio Segment [Member]
Total Loans Collectively Evaluated for Impairment	1,468,890	1,459,594
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	11,767	11,192
Total Loans	1,468,890	1,459,594
Total Ending ALLL	11,767	11,192	11,631	11,813
Owner Occupied Property [Member] | Commercial Real Estate Portfolio Segment [Member]
Total Loans Individually Evaluated for Impairment	1,461	1,486
Total Loans Collectively Evaluated for Impairment	210,112	174,637
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	2,235	1,774
Total Loans	211,573	176,123
Total Ending ALLL	2,235	1,774	1,683	1,679
Investment Property [Member] | Commercial Real Estate Portfolio Segment [Member]
Total Loans Individually Evaluated for Impairment	11,297	11,335
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	211	214
Total Loans Collectively Evaluated for Impairment	778,893	740,923
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	10,672	10,695
Total Loans	790,190	752,258
Total Ending ALLL	10,883	10,909	8,527	7,590
Construction Loans [Member] | Commercial Portfolio Segment [Member]
Total Loans Collectively Evaluated for Impairment	96	1,497
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	1	9
Total Loans	96	1,497
Total Ending ALLL	1	9	2	2
Commercial and Industrial Sector [Member] | Commercial Portfolio Segment [Member]
Total Loans Individually Evaluated for Impairment	68	154
Ending ALLL Attributable to Loans Individually Evaluated for Impairment	68	154
Total Loans Collectively Evaluated for Impairment	214,395	213,829
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	4,244	4,010
Total Loans	214,463	213,983
Total Ending ALLL	4,312	4,164	2,691	2,209
Agricultural Sector [Member]
Total Loans Collectively Evaluated for Impairment	166	169
Ending ALLL Attributable to Loans Collectively Evaluated for Impairment	2	2
Total Loans	166	169
Total Ending ALLL	$ 2	$ 2	$ 2	$ 2