ALLOWANCE FOR LOAN LOSSES AND RESERVE FOR FIRST LOSS POSITION ON MULTIFAMILY LOANS SOLD TO FNMA (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses at Period End on Substandard Non Impaired Loans	$ 375				$ 375				$ 795
Increase (Decrease) in the balance of Substandard non-impaired loans					(4,936)
Financing Receivable Special Mention Allowance For Loan Losses period end balance	235				235				145
Financing Receivable Special Mention Balance Increase (Decrease)					5,631
Reserve For First Loss Position [Abstract]
Outstanding balance of multifamily loans serviced for FNMA at period end	229,165		291,733		229,165		291,733
First Loss Position Loans Serviced For Fnma	15,428		16,356		15,428		16,356
Balance at beginning of period	1,291		2,958		1,383		2,993
Transfer of specific reserve for serviced loans re-acquired by the Bank	0		0		0		0
Credit for losses on problem loans(1)	(102)	[1]	(967)	[1]	(194)	[1]	(967)	[1]
Charge-offs and other net reductions in balance	(1)		(307)		(1)		(342)
Balance at period end	1,188		1,684		1,188		1,684
One To Four Family Residential And Cooperative Unit Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	350		313		344		480
Provision (credit) for loan losses	12		40		104		403
Charge-offs	(11)		(110)		(99)		(640)
Recoveries	1		15		3		15
Financing Receivable Allowance For Credit Losses Transfers			0				0
Ending balance	352		258		352		258
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	1,206				1,206				1,291
Ending balance - loans collectively evaluated for impairment	79,904				79,904				90,585
Allowance balance associated with loans individually evaluated for impairment	6				6				7
Allowance balance associated with loans collectivelly evaluated for impairment	346				346				337
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	1,073				1,073				1,079
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	257				257				258
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	995	[2]			995	[2]			1,079	[2]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	212	[2]			212	[2]			212	[2]
Impaired Financing Receivables With No Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivables With Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	6				6				7
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	996		855		1,024		948
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	212		212		211		612
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	6		25		17		33
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	5		5		9		9
Multifamily Residential And Residential Mixed Use Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	13,890		13,871		14,299		14,313
Provision (credit) for loan losses	755		1,840		456		2,237
Charge-offs	(46)		(1,241)		(156)		(2,138)
Recoveries	21		63		21		87
Financing Receivable Allowance For Credit Losses Transfers			18				52
Ending balance	14,620		14,551		14,620		14,551
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	3,212				3,212				2,460
Ending balance - loans collectively evaluated for impairment	2,781,994				2,781,994				2,673,909
Allowance balance associated with loans individually evaluated for impairment	0				0				0
Allowance balance associated with loans collectivelly evaluated for impairment	14,620				14,620				14,299
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	3,212				3,212				2,767
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0				0				0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,212	[2]			3,212	[2]			2,460	[2]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	[2]			0	[2]			0	[2]
Impaired Financing Receivables With No Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivables With Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	2,779		6,733		2,673		7,131
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0		0		0		700
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	32		124		80		255
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		0		0		0
Mixed Use Commercial Real Estate Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	2,590		2,249		2,474		1,528
Provision (credit) for loan losses	(360)		47		(273)		1,300
Charge-offs	(15)		(136)		(15)		(663)
Recoveries	0		11		29		11
Financing Receivable Allowance For Credit Losses Transfers			10				5
Ending balance	2,215		2,181		2,215		2,181
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	1,868				1,868				1,900
Ending balance - loans collectively evaluated for impairment	339,189				339,189				338,233
Allowance balance associated with loans individually evaluated for impairment	0				0				0
Allowance balance associated with loans collectivelly evaluated for impairment	2,215				2,215				2,474
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	1,867				1,867				1,900
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0				0				0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,867	[2]			1,867	[2]			1,900	[2]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	[2]			0	[2]			0	[2]
Impaired Financing Receivables With No Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivables With Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	1,875		1,721		1,883		3,074
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0		0		0		320
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	40		19		92		44
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		0		0		0
Total Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	20,504		19,444		20,523		20,228
Provision (credit) for loan losses	23		2,274		174		3,725
Charge-offs	(72)		(1,650)		(274)		(3,929)
Recoveries	23		90		55		114
Financing Receivable Allowance For Credit Losses Transfers			62				82
Ending balance	20,478		20,220		20,478		20,220
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	47,302				47,302				53,144
Ending balance - loans collectively evaluated for impairment	3,556,945				3,556,945				3,450,241
Allowance balance associated with loans individually evaluated for impairment	522				522				520
Allowance balance associated with loans collectivelly evaluated for impairment	19,956				19,956				20,003
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	33,090				33,090				39,162
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	15,448				15,448				15,534
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	31,899	[2]			31,899	[2]			37,656	[2]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	15,403	[2]			15,403	[2]			15,488	[2]
Impaired Financing Receivables With No Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivables With Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	522				522				520
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	32,829		44,535		34,438		38,574
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	15,410		15,534		15,436		24,933
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	442		585		951		1,246
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	143		194		405		388
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	26		24		27		26
Provision (credit) for loan losses	5		1		10		7
Charge-offs	(7)		(2)		(13)		(10)
Recoveries	0		0		0		0
Financing Receivable Allowance For Credit Losses Transfers			0				0
Ending balance	24		23		24		23
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	0				0				0
Ending balance - loans collectively evaluated for impairment	2,517				2,517				2,423
Allowance balance associated with loans individually evaluated for impairment	0				0				0
Allowance balance associated with loans collectivelly evaluated for impairment	24				24				27
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	3,652		3,011		3,382		3,783
Provision (credit) for loan losses	(374)		347		(101)		(94)
Charge-offs	0		(163)		(4)		(485)
Recoveries	1		1		2		1
Financing Receivable Allowance For Credit Losses Transfers			34				25
Ending balance	3,279		3,230		3,279		3,230
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	41,016				41,016				47,493
Ending balance - loans collectively evaluated for impairment	355,520				355,520				347,038
Allowance balance associated with loans individually evaluated for impairment	516				516				513
Allowance balance associated with loans collectivelly evaluated for impairment	2,763				2,763				2,869
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	26,938				26,938				33,416
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	15,191				15,191				15,276
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	25,825	[2]			25,825	[2]			32,217	[2]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	15,191	[2]			15,191	[2]			15,276	[2]
Impaired Financing Receivables With No Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivables With Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	516				516				513
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	27,179		35,226		28,858		27,421
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	15,198		15,322		15,225		23,301
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	364		417		762		914
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	138		189		396		379
Construction Loan Receivable [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	22		0		24		124
Provision (credit) for loan losses	(10)		0		(12)		(121)
Charge-offs	0		0				(3)
Recoveries	0		0		0		0
Financing Receivable Allowance For Credit Losses Transfers			0				0
Ending balance	12		0		12		0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	0				0				0
Ending balance - loans collectively evaluated for impairment	338				338				476
Allowance balance associated with loans individually evaluated for impairment	0				0				0
Allowance balance associated with loans collectivelly evaluated for impairment	12				12				24
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	0				0				0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0				0				0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	[2]			0	[2]			0	[2]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	[2]			0	[2]			0	[2]
Impaired Financing Receivables With No Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivables With Allocated Reserves Within Allowance For Loan Losses Recognized For Impaired Receivables	0				0				0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	0		0		0		0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0		0		0		0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0		0		0		0
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	$ 0		$ 0		$ 0		$ 0

[1] (1) Amount recognized as a component of mortgage banking income during the period.

[2] (1)The recorded investment excludes accrued interest receivable and loan origination fees, net, due to immateriality.