Investments: Narrative (Details) - USD ($)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Investments [Abstract]    
Investments pledged as collateral for public deposits $ 17,400,000 $ 16,300,000
Unrealized loss 791,000 387,000
Fair Value $ 78,317,000 $ 31,202,000