FAIR VALUE OF FINANCIAL INSTRUMENTS, Balance Sheet Groupings (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
ASSETS
Investment securities held to maturity (TRUPS)	$ 5,820	$ 5,163
Premises held for sale	0	3,624
Estimate of Fair Value, Fair Value Disclosure [Member]
ASSETS
Cash and due from banks	66,120	45,777
Investment securities held to maturity (TRUPS)	5,127	5,163
Loans, net	4,013,267	3,718,604
Loans held for sale		0
Premises held for sale		4,400
Accrued Interest Receivable	12,576	12,066
Mortgage servicing rights (MSR)	449	1,006
FHLBNY capital stock	0	0
Liabilities [Abstract]
Savings, money market and checking accounts	1,718,523	1,678,737
Certificates of Deposit (CDs)	879,045	839,059
Escrow and other deposits	110,062	69,404
FHLBNY advances	1,053,644	934,336
Trust preferred securities payable	70,680	70,680
Accrued Interest Payable	2,969	2,642
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 1 [Member]
ASSETS
Cash and due from banks	66,120	45,777
Investment securities held to maturity (TRUPS)	0	0
Loans, net	0	0
Loans held for sale		0
Premises held for sale		0
Accrued Interest Receivable	1	0
Mortgage servicing rights (MSR)	0	0
FHLBNY capital stock	0	0
Liabilities [Abstract]
Savings, money market and checking accounts	1,718,523	1,678,737
Certificates of Deposit (CDs)	0	0
Escrow and other deposits	110,062	69,404
FHLBNY advances	0	0
Trust preferred securities payable	0	0
Accrued Interest Payable	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
ASSETS
Cash and due from banks	0	0
Investment securities held to maturity (TRUPS)	0	0
Loans, net	0	0
Loans held for sale		0
Premises held for sale		4,400
Accrued Interest Receivable	124	178
Mortgage servicing rights (MSR)	449	1,006
FHLBNY capital stock	0	0
Liabilities [Abstract]
Savings, money market and checking accounts	0	0
Certificates of Deposit (CDs)	879,045	839,059
Escrow and other deposits	0	0
FHLBNY advances	1,053,644	934,336
Trust preferred securities payable	70,680	70,680
Accrued Interest Payable	2,969	2,642
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 3 [Member]
ASSETS
Cash and due from banks	0	0
Investment securities held to maturity (TRUPS)	5,127	5,163
Loans, net	4,013,267	3,718,604
Loans held for sale		0
Premises held for sale		0
Accrued Interest Receivable	12,451	11,888
Mortgage servicing rights (MSR)	0	0
FHLBNY capital stock	0	0
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
Carrying (Reported) Amount, Fair Value Disclosure [Member]
ASSETS
Cash and due from banks	66,120	45,777
Investment securities held to maturity (TRUPS)	5,324	5,341
Loans, net	3,924,965	3,679,366
Loans held for sale		0
Premises held for sale		3,624
Accrued Interest Receivable	12,576	12,066
Mortgage servicing rights (MSR)	449	628
FHLBNY capital stock	53,593	48,051
Liabilities [Abstract]
Savings, money market and checking accounts	1,718,523	1,678,737
Certificates of Deposit (CDs)	868,451	828,409
Escrow and other deposits	110,062	69,404
FHLBNY advances	1,033,150	910,000
Trust preferred securities payable	70,680	70,680
Accrued Interest Payable	$ 2,969	$ 2,642