LOANS RECEIVABLE AND CREDIT QUALITY, Past Due Financing Receivbles (Details) $ in Thousands	Jun. 30, 2015 USD ($) Loan		Dec. 31, 2014 USD ($) Loan
Financing Receivable, Recorded Investment, Aging [Abstract]
Number Of Loans 90 Days or More Past Due And Still Accruing Pending Refinancing | Loan	3		8
Loans 90 Days or More Past Due And Still Accruing Pending Refinancing	$ 1,044		$ 3,333
One To Four Family Residential And Cooperative Unit Allowance [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Current	70,042		71,950
Financing Receivable, Recorded Investment, Past Due	833		1,550
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0		0
Non-accrual	749	[1]	1,310	[2]
Loans and Leases Receivable, Other, Net of Deferred Income	70,875		73,500
One To Four Family Residential And Cooperative Unit Allowance [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	79		240
One To Four Family Residential And Cooperative Unit Allowance [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	5		0
Multifamily Residential and Residential Mixed Use [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Current	3,433,148		3,294,172
Financing Receivable, Recorded Investment, Past Due	404		4,276
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	144		2,922
Non-accrual	0	[1]	167	[2]
Loans and Leases Receivable, Other, Net of Deferred Income	3,433,552		3,298,448
Multifamily Residential and Residential Mixed Use [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	260		1,187
Multifamily Residential and Residential Mixed Use [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
Mixed Use Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Current	357,579		328,256
Financing Receivable, Recorded Investment, Past Due	409		411
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	409		411
Non-accrual	0	[1]	0	[2]
Loans and Leases Receivable, Other, Net of Deferred Income	357,988		328,667
Mixed Use Commercial Real Estate [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
Mixed Use Commercial Real Estate [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Current	441,196		412,079
Financing Receivable, Recorded Investment, Past Due	698		4,717
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	491		0
Non-accrual	207	[1]	4,717	[2]
Loans and Leases Receivable, Other, Net of Deferred Income	441,894		416,796
Commercial Real Estate [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
Commercial Real Estate [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
Construction Loan Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Current	0		0
Financing Receivable, Recorded Investment, Past Due	0		0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0		0
Non-accrual	0	[1]	0	[2]
Loans and Leases Receivable, Other, Net of Deferred Income	0		0
Construction Loan Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
Construction Loan Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
Consumer Loan [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Current	1,946		1,823
Financing Receivable, Recorded Investment, Past Due	8		6
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0		0
Non-accrual	3	[1]	4	[2]
Loans and Leases Receivable, Other, Net of Deferred Income	1,954		1,829
Consumer Loan [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	5		2
Consumer Loan [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
Total Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Current	4,301,965		4,106,457
Financing Receivable, Recorded Investment, Past Due	2,344		10,954
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	1,044		3,333
Non-accrual	956	[1]	6,194	[2]
Loans and Leases Receivable, Other, Net of Deferred Income	4,304,309		4,117,411
Total Real Estate Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	339		1,427
Total Real Estate Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	$ 5		$ 0

[1] Includes all loans on non-accrual status regardless of the number of days such loans were delinquent as of June 30, 2015.

[2] Includes all loans on non-accrual status regardless of the number of days such loans were delinquent as of December 31, 2014.