FEDERAL HOME LOAN BANK ADVANCES AND OTHER BORROWINGS (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Advances from Federal Home Loan Banks	$ 105,000	$ 108,000
FHLB interest rate	3.20%	3.17%
Advances with fixed maturity dates	$ 105,000	$ 108,000
Weighted average interest rate on fixed maturity advances	3.20%	3.17%
Residential mortgages pledged as collateral for advances	$ 506,500	$ 824,300
Multifamily mortgage loans pledged as collateral for advances	496,100	1,000,000
Investment pledges against advances	46,700	58,500
Overnight borrowings with FHLB	0	$ 0
Unused commitments from FHLB	1,300,000
Unused short-term or overnight borrowings from correspondent banks	22,000
Unused short-term or overnight borrowings from FRB	$ 1,400,000