DERIVATIVES AND HEDGING ACTIVITIES, Offsetting of Derivative Assets (Details) - Other Assets [Member] - Interest Rate Swaps Related to FHLBNY Advances [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	$ 3,258	$ 4,669
Gross amounts offset in the statement of financial position	(3,970)	(2,097)
Net amounts of assets presented in the statement of financial position	(712)	2,572
Gross amounts not offset in the statement of financial position, financial instruments	0	0
Gross amounts not offset in the statement of financial position, cash collateral received	0	0
Net amount	$ (712)	$ 2,572