INVESTMENT SECURITIES: (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Investment Securities Activity
Due in one year or less, Amortized Cost	$ 4
Due after one year through five years, Amortized Cost	3,494
Due after five years through ten years, Amortized Cost	16,042
Due after ten years, Amortized Cost	49,285
Amortized Cost, Total	68,825	$ 71,839
Due in one year or less, Fair Value	4
Due after one year through five years, Fair Value	3,407
Due after five years through ten years, Fair Value	15,802
Due after ten years, Fair Value	47,820
Approximate Fair Value	$ 67,033	$ 71,088
Due in one year or less, Weighted Average Yield	1.63%
Due after one year through five years, Weighted Average Yield	1.92%
Due after five years through ten years, Weighted Average Yield	3.20%
Due after ten years, Weighted Average Yield	2.31%
Weighted Average Yield, Total	2.49%