Investments - Credit losses rollforward (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Credit losses on fixed maturity securities | ||
| Beginning balance | $ 753 | $ 557 |
| Percent change, Net realized gains on sales | 162.60% | |
| Additions for: Previously impaired securities | $ 278 | 0 |
| Additions for: Newly impaired securities | 7 | 10 |
| Reductions for: Securities sold and paid down | (41) | (24) |
| Ending balance | $ 996 | $ 542 |