LOANS, Past Due (Details) $ in Thousands	Dec. 31, 2015 USD ($) Loan		Dec. 31, 2014 USD ($) Loan
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of Real Estate Loans More Than 90 Days Past Due On Contractual Balloon Payment | Loan	12		8
Real Estate Loans More Than 90 Days Past Due On Contractual Balloon Payment	$ 4,532		$ 3,333
One-to Four-Family Residential and Cooperative Unit [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-accrual	1,113	[1]	1,310	[2]
Total Past Due	1,865		1,550
Current	70,230		71,950
Loans and Leases Receivable, Other, Net of Deferred Income	72,095		73,500
One-to Four-Family Residential and Cooperative Unit [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	127		240
One-to Four-Family Residential and Cooperative Unit [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0
One-to Four-Family Residential and Cooperative Unit [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	625		0
Multifamily Residential and Residential Mixed Use [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-accrual	287	[1]	167	[2]
Total Past Due	5,036		4,276
Current	3,754,871		3,294,172
Loans and Leases Receivable, Other, Net of Deferred Income	3,759,907		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	2,235		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
Multifamily Residential and Residential Mixed Use [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	2,514		2,922
Mixed Use Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-accrual	0	[1]	0	[2]
Total Past Due	812		411
Current	376,463		328,256
Loans and Leases Receivable, Other, Net of Deferred Income	377,275		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	406		0
Mixed Use Commercial Real Estate [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	406		411
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-accrual	207	[1]	4,717	[2]
Total Past Due	1,394		4,717
Current	484,515		412,079
Loans and Leases Receivable, Other, Net of Deferred Income	485,909		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	200		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
Commercial Real Estate [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	987		0
Construction [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-accrual	0	[1]	0	[2]
Total Past Due	0		0
Current	0		0
Loans and Leases Receivable, Other, Net of Deferred Income	0		0
Construction [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 [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 [Member] | Financing Receivables, Equal to Greater than 90 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]
Non-accrual	1,607	[1]	6,194	[2]
Total Past Due	9,107		10,954
Current	4,686,079		4,106,457
Loans and Leases Receivable, Other, Net of Deferred Income	4,695,186		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	2,562		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	406		0
Total Real Estate Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	4,532		3,333
Consumer Loan [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-accrual	4	[1]	4	[2]
Total Past Due	6		6
Current	1,584		1,823
Loans and Leases Receivable, Other, Net of Deferred Income	1,590		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	1		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	1		0
Consumer Loan [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Financing Receivable, Recorded Investment, Past Due	$ 0		$ 0

[1] Includes all loans on non-accrual status regardless of the number of days such loans were delinquent as of December 31, 2015.

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