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				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	$ 27,090				$ 27,090				$ 39,162
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	15,377				15,377				15,534
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	25,749	[1]			25,749	[1]			37,656	[1]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	15,333	[1]			15,333	[1]			15,488	[1]
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	490				490				520
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	28,825		40,471		32,265		38,310
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	15,367		15,496		15,411		22,566
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	264		480		1,215		1,727
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	280		194		685		581
Allowance for Loan Losses at Period End on Substandard Non Impaired Loans	31				31				795
Increase (Decrease) in the balance of Substandard non-impaired loans					(5,568)
Financing Receivable Special Mention Allowance For Loan Losses period end balance	148				148				145
Financing Receivable Special Mention Balance Increase (Decrease)					12,644
Reserve For First Loss Position [Abstract]
Outstanding balance of multifamily loans serviced for FNMA at period end	216,073		279,830		216,073		279,830
First Loss Position Loans Serviced For Fnma	15,428		16,356		15,428		16,356
Reserve Liability On The First Loss Position [Roll Forward]
Balance at beginning of period	1,188		1,684		1,383		2,993
Credit for losses on problem loans(1)	(50)	[2]	(140)	[2]	(245)	[2]	(1,107)	[2]
Charge-offs and other net reductions in balance	(38)		0		(38)		(342)
Balance at period end	1,100		1,544		1,100		1,544
One To Four Family Residential And Cooperative Unit Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	352		258		344		480
Provision (credit) for loan losses	(75)		557		29		959
Charge-offs	(11)		(134)		(110)		(774)
Recoveries	8		(1)		11		17
Financing Receivable Allowance For Credit Losses Transfers							0
Ending balance	274		682		274		682
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	1,203				1,203				1,291
Ending balance - loans collectively evaluated for impairment	77,301				77,301				90,585
Allowance balance associated with loans individually evaluated for impairment	6				6				7
Allowance balance associated with loans collectivelly evaluated for impairment	268				268				337
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	1,070				1,070				1,079
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	256				256				258
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	991	[1]			991	[1]			1,079	[1]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	212	[1]			212	[1]			212	[1]
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	993		629		1,016		814
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	212		212		212		511
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	11		15		27		48
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	5		5		14		14
Multifamily Residential And Residential Mixed Use Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	14,620		14,551		14,299		14,313
Provision (credit) for loan losses	1,382		(761)		1,840		1,477
Charge-offs	(205)		(242)		(362)		(2,381)
Recoveries	13		686		33		773
Financing Receivable Allowance For Credit Losses Transfers							52
Ending balance	15,810		14,234		15,810		14,234
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	3,891				3,891				2,460
Ending balance - loans collectively evaluated for impairment	2,860,933				2,860,933				2,673,909
Allowance balance associated with loans individually evaluated for impairment	0				0				0
Allowance balance associated with loans collectivelly evaluated for impairment	15,810				15,810				14,299
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	4,040				4,040				2,767
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0				0				0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,891	[1]			3,891	[1]			2,460	[1]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	[1]			0	[1]			0	[1]
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	3,552		4,787		2,977		6,178
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0		0		0		525
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	49		49		129		305
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 [Roll Forward]
Beginning balance	2,215		2,181		2,474		1,528
Provision (credit) for loan losses	(443)		143		(716)		1,442
Charge-offs	0		(8)		(15)		(670)
Recoveries	0		0		29		11
Financing Receivable Allowance For Credit Losses Transfers							5
Ending balance	1,772		2,316		1,772		2,316
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	711				711				1,900
Ending balance - loans collectively evaluated for impairment	334,939				334,939				338,233
Allowance balance associated with loans individually evaluated for impairment	0				0				0
Allowance balance associated with loans collectivelly evaluated for impairment	1,772				1,772				2,474
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	711				711				1,900
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0				0				0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	711	[1]			711	[1]			1,900	[1]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	[1]			0	[1]			0	[1]
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	1,289		1,459		1,590		2,670
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0		0		0		240
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	17		12		110		56
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 [Roll Forward]
Beginning balance	20,478		20,220		20,523		20,228
Provision (credit) for loan losses	235		123		411		3,848
Charge-offs	(217)		(398)		(492)		(4,328)
Recoveries	21		723		75		838
Financing Receivable Allowance For Credit Losses Transfers							82
Ending balance	20,517		20,668		20,517		20,668
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	41,082				41,082				53,144
Ending balance - loans collectively evaluated for impairment	3,625,857				3,625,857				3,450,241
Allowance balance associated with loans individually evaluated for impairment	490				490				520
Allowance balance associated with loans collectivelly evaluated for impairment	20,027				20,027				20,003
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	24		23		27		26
Provision (credit) for loan losses	5		3		14		10
Charge-offs	(6)		0		(18)		(10)
Recoveries	0		0		0		0
Financing Receivable Allowance For Credit Losses Transfers							0
Ending balance	23		26		23		26
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	2,109				2,109				2,423
Allowance balance associated with loans individually evaluated for impairment	0				0				0
Allowance balance associated with loans collectivelly evaluated for impairment	23				23				27
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,279		3,230		3,382		3,783
Provision (credit) for loan losses	(618)		157		(719)		64
Charge-offs	(1)		(14)		(5)		(500)
Recoveries	0		36		2		37
Financing Receivable Allowance For Credit Losses Transfers							25
Ending balance	2,660		3,409		2,660		3,409
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Ending balance - loans individually evaluated for impairment	35,277				35,277				47,493
Ending balance - loans collectively evaluated for impairment	352,385				352,385				347,038
Allowance balance associated with loans individually evaluated for impairment	484				484				513
Allowance balance associated with loans collectivelly evaluated for impairment	2,176				2,176				2,869
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	21,269				21,269				33,416
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	15,121				15,121				15,276
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	20,156	[1]			20,156	[1]			32,217	[1]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	15,121	[1]			15,121	[1]			15,276	[1]
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	484				484				513
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	22,991		33,596		26,682		28,648
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	15,155		15,284		15,199		21,290
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	187		404		949		1,318
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	275		189		671		567
Construction Loan Receivable [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	12		0		24		124
Provision (credit) for loan losses	(11)		27		(23)		(94)
Charge-offs	0		0		0		(3)
Recoveries	0		0		0		0
Financing Receivable Allowance For Credit Losses Transfers							0
Ending balance	1		27		1		27
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	299				299				476
Allowance balance associated with loans individually evaluated for impairment	0				0				0
Allowance balance associated with loans collectivelly evaluated for impairment	1				1				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	[1]			0	[1]			0	[1]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	[1]			0	[1]			0	[1]
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] The recorded investment excludes accrued interest receivable and loan origination fees, net, due to immateriality.

[2] Amount recognized as a component of mortgage banking income during the period.