GOODWILL AND INTANGIBLE ASSETS: (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 15,607	$ 15,505
Accumulated Amortization	12,429	11,604
Customer list intangible
Finite-Lived Intangible Assets [Line Items]
Gross Amount	4,771	4,669
Accumulated Amortization	4,309	4,227
Core deposit intangible
Finite-Lived Intangible Assets [Line Items]
Gross Amount	10,836	10,836
Accumulated Amortization	$ 8,120	$ 7,377