GOODWILL AND INTANGIBLE ASSETS: (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 15,505	$ 15,505
Accumulated Amortization	11,604	10,570
Customer list intangible
Finite-Lived Intangible Assets [Line Items]
Gross Amount	4,669	4,669
Accumulated Amortization	4,227	4,120
Core deposit intangible
Finite-Lived Intangible Assets [Line Items]
Gross Amount	10,836	10,836
Accumulated Amortization	$ 7,377	$ 6,450