FEDERAL HOME LOAN BANK ADVANCES AND OTHER BORROWINGS (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Advances from Federal Home Loan Banks	$ 108,000	$ 37,900
FHLB interest rate	3.17%	2.20%
Advances with fixed maturity dates	$ 108,000	$ 28,900
Weighted average interest rate on fixed maturity advances	3.17%	1.96%
Residential mortgages pledged as collateral for advances	$ 496,100	$ 1,000,000
Multifamily mortgage loans pledged as collateral for advances	550,000	1,100,000
Investment pledges against advances	58,500	13,500
Callable variable rate advances		$ 9,000
Weighted average interest rate on variable advances (in percent)		2.95%
Overnight borrowings of debt	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	$ 1,300,000