LOANS RECEIVABLE AND CREDIT QUALITY, Credit Quality Indicators (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
One-to four Family Residential and Cooperative Unit [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	$ 10,246	[1]	$ 11,370	[1]
Financing Receivable, Net	74,442		73,956
Multifamily Residential and Residential Mixed Use [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	0	[1]	0	[1]
Financing Receivable, Net	3,161,980		2,922,550
Mixed Use Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	0	[1]	0	[1]
Financing Receivable, Net	324,327		375,910
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	0	[1]	0	[1]
Financing Receivable, Net	411,802		324,696
Construction Loan Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	0	[1]	0	[1]
Financing Receivable, Net	0		268
Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	2,440		2,139
Total Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	10,246	[1]	11,370	[1]
Financing Receivable, Net	3,972,551		3,697,380
Pass [Member] | One-to four Family Residential and Cooperative Unit [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	54,486		53,472
Pass [Member] | Multifamily Residential and Residential Mixed Use [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	3,143,010		2,900,979
Pass [Member] | Mixed Use Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	312,749		364,808
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	386,816		299,122
Pass [Member] | Construction Loan Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	0		0
Pass [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	2,435		2,136
Pass [Member] | Total Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	3,897,061		3,618,381
Special Mention [Member] | One-to four Family Residential and Cooperative Unit [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	7,386		6,651
Special Mention [Member] | Multifamily Residential and Residential Mixed Use [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	15,182		17,938
Special Mention [Member] | Mixed Use Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	5,143		5,203
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	14,390		4,420
Special Mention [Member] | Construction Loan Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	0		0
Special Mention [Member] | Total Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	42,101		34,212
Substandard [Member] | One-to four Family Residential and Cooperative Unit [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	2,324		2,463
Substandard [Member] | Multifamily Residential and Residential Mixed Use [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	3,788		3,633
Substandard [Member] | Mixed Use Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	6,435		4,579
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	10,596		21,154
Substandard [Member] | Construction Loan Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	0		268
Substandard [Member] | Total Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	23,143		32,097
Doubtful [Member] | One-to four Family Residential and Cooperative Unit [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	0		0
Doubtful [Member] | Multifamily Residential and Residential Mixed Use [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	0		0
Doubtful [Member] | Mixed Use Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	0		1,320
Doubtful [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	0		0
Doubtful [Member] | Construction Loan Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	0		0
Doubtful [Member] | Total Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Individually Assigned Credit Rating	0		1,320
Non Accrual Financing Receivable [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Not Individually Assigned Credit Rating	$ 5		$ 3

[1] Amount comprised of fully performing one- to four-family residential and condominium and cooperative unit loans with balances equal to or less than the FNMA Limits.