Catastrophe Loss Reserve and Trust Fund (Details) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Catastrophe Loss Reserve and Trust Fund [Abstract] | ||
| Maximum contribution rate which increases catastrophe reserve | 5.00% | |
| Minimum percentage of reserve to catastrophe exposure | 8.00% | |
| Interest earning assets | $ 47,630 | $ 46,221 |
| Restricted catastrophe loss reserve balance | $ 44,823 | $ 43,041 |