FAIR VALUE OF FINANCIAL INSTRUMENTS, Balance Sheet Groupings (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Carrying Amount [Member]
ASSETS
Cash and due from banks	$ 64,154	$ 78,187
Federal funds sold and other short term investments	0	250
Investment securities held to maturity (TRUPS)	5,242	5,367
Loans, net (excluding impaired loans carried at fair value)	4,678,262	4,096,347
Accrued Interest Receivable	13,486	12,664
FHLBNY capital stock	58,713	58,407
Liabilities [Abstract]
Savings, money market and checking accounts	2,325,463	1,733,474
Certificates of Deposit (CDs)	858,847	926,318
Escrow and other deposits	77,130	91,921
FHLBNY advances	1,166,725	1,173,725
Trust preferred securities payable	70,680	70,680
Accrued Interest Payable	2,259	2,729
Fair Value [Member]
ASSETS
Cash and due from banks	64,154	78,187
Federal funds sold and other short term investments	0	250
Investment securities held to maturity (TRUPS)	7,051	6,315
Loans, net (excluding impaired loans carried at fair value)	4,722,803	4,188,137
Accrued Interest Receivable	13,486	12,664
Liabilities [Abstract]
Savings, money market and checking accounts	2,325,463	1,733,474
Certificates of Deposit (CDs)	865,581	934,324
Escrow and other deposits	77,130	91,921
FHLBNY advances	1,170,274	1,186,069
Trust preferred securities payable	69,973	70,680
Accrued Interest Payable	2,259	2,729
Fair Value [Member] | Fair Value, Inputs, Level 1 [Member]
ASSETS
Cash and due from banks	64,154	78,187
Federal funds sold and other short term investments	0	250
Investment securities held to maturity (TRUPS)	0	0
Loans, net (excluding impaired loans carried at fair value)	0	0
Accrued Interest Receivable	0	2
Liabilities [Abstract]
Savings, money market and checking accounts	2,325,463	1,733,474
Certificates of Deposit (CDs)	0	0
Escrow and other deposits	77,130	91,921
FHLBNY advances	0	0
Trust preferred securities payable	0	0
Accrued Interest Payable	0	0
Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]
ASSETS
Cash and due from banks	0	0
Federal funds sold and other short term investments	0	0
Investment securities held to maturity (TRUPS)	0	0
Loans, net (excluding impaired loans carried at fair value)	0	0
Accrued Interest Receivable	19	104
Liabilities [Abstract]
Savings, money market and checking accounts	0	0
Certificates of Deposit (CDs)	865,581	934,324
Escrow and other deposits	0	0
FHLBNY advances	1,170,274	1,186,069
Trust preferred securities payable	69,973	70,680
Accrued Interest Payable	2,259	2,729
Fair Value [Member] | Fair Value, Inputs, Level 3 [Member]
ASSETS
Cash and due from banks	0	0
Federal funds sold and other short term investments	0	0
Investment securities held to maturity (TRUPS)	7,051	6,315
Loans, net (excluding impaired loans carried at fair value)	4,722,803	4,188,137
Accrued Interest Receivable	13,467	12,558
Liabilities [Abstract]
Savings, money market and checking accounts	0	0
Certificates of Deposit (CDs)	0	0
Escrow and other deposits	0	0
FHLBNY advances	0	0
Trust preferred securities payable	0	0
Accrued Interest Payable	0	0
Investment securities held to maturity (TRUPS)	$ 7,051	$ 6,315