Investments: Gain/Loss on Investments (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Investments [Abstract] | |||
| Proceeds | $ 26,437 | $ 27,327 | $ 4,980 |
| Gross gains | 245 | 449 | 0 |
| Gross losses | $ (195) | $ (357) | $ (20) |