LOANS AND LEASES (Schedule of Loan Balances by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Total loans	$ 3,893,918	$ 3,924,312
Net deferred costs	3,498	3,619
Total loans including net deferred costs	$ 3,897,416	$ 3,927,931
Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	100.00%	100.00%
Residential Portfolio Segment [Member] \| Primary Residential Mortgages [Member]
Total loans	$ 598,299	$ 600,891
Residential Portfolio Segment [Member] \| Primary Residential Mortgages [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	15.37%	15.31%
Residential Portfolio Segment [Member] \| Home Equity Lines of Credit [Member]
Total loans	$ 57,636	$ 62,191
Total loans including net deferred costs	$ 57,639	$ 62,191
Residential Portfolio Segment [Member] \| Home Equity Lines of Credit [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	1.48%	1.58%
Residential Portfolio Segment [Member] \| Multifamily Property [Member]
Total loans	$ 1,104,406	$ 1,135,805
Total loans including net deferred costs	$ 1,104,406	$ 1,135,805
Residential Portfolio Segment [Member] \| Multifamily Property [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	28.36%	28.94%
Residential Portfolio Segment [Member] \| Junior Lien [Member]
Total loans	$ 7,429	$ 7,418
Residential Portfolio Segment [Member] \| Junior Lien [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	0.19%	0.19%
Commercial Real Estate Portfolio Segment [Member] \| Owner Occupied Property [Member]
Total loans	$ 251,948	$ 261,193
Commercial Real Estate Portfolio Segment [Member] \| Owner Occupied Property [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	6.47%	6.65%
Commercial Real Estate Portfolio Segment [Member] \| Investment Property [Member]
Total loans	$ 1,005,724	$ 1,001,918
Commercial Real Estate Portfolio Segment [Member] \| Investment Property [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	25.83%	25.53%
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Total loans	$ 86	$ 86
Commercial Portfolio Segment [Member] \| Construction Loans [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)		0.01%
Consumer and Other Loans [Member]
Total loans	$ 59,138	$ 65,180
Consumer and Other Loans [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	1.52%	1.66%
Commercial and Industrial Sector [Member] \| Commercial Portfolio Segment [Member]
Total loans	$ 633,590	$ 616,838
Commercial and Industrial Sector [Member] \| Commercial Portfolio Segment [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	16.27%	15.72%
Lease Financing [Member]
Total loans	$ 175,517	$ 172,643
Lease Financing [Member] \| Commercial Portfolio Segment [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)	4.51%	4.40%
Agricultural Sector [Member]
Total loans	$ 145	$ 149
Agricultural Sector [Member] \| Customer Concentration Risk [Member] \| Loans and Finance Receivables, Gross [Member]
Total loans (in percent)		0.01%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

+ Details

Name:	us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

+ Details

Name:	us-gaap_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant