DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Derivatives Not Designated as Hedging, by Balance Sheet Location) (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 5,083	$ 8,330
Derivative Liability, Fair Value, Gross Liability		5,083	8,330
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		5,083	8,330
Derivative Liability, Fair Value, Gross Liability		5,083	8,330
Interest Rate Swap [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount		282,300
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount		357,855	423,424
Derivative Liability, Notional Amount		345,810	346,842
Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	5,159	8,152
Not Designated as Hedging Instrument [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[2]	4,837	7,959
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount		285,047	309,936
Derivative Liability, Notional Amount		285,047	309,936
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Loans Receivable [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		499	822
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	4,636	7,670
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[2]	4,636	7,670
Not Designated as Hedging Instrument [Member] | Mortgage Loan Commitments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount		29,739	42,296
Derivative Liability, Notional Amount		13,763	27,191
Not Designated as Hedging Instrument [Member] | Mortgage Loan Commitments [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	225	30
Not Designated as Hedging Instrument [Member] | Mortgage Loan Commitments [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[2]	153	174
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount		43,069	71,192
Derivative Liability, Notional Amount		47,000	9,715
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	298	452
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	[2]	$ 48	$ 115

[1] Included in Other Assets on the Consolidated Statements of Financial Condition, with the exception of those interest rate swaps from prior to 2009 that were not designated in hedge relationships (with a fair value of $499,000 at December 31, 2017 and $822,000 at December 31, 2016), which are included in Loans Receivable.

[2] Included in Other Liabilities on the Consolidated Statements of Financial Condition.