Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands |
Mar. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Statement of Financial Position [Abstract] | ||
| Fixed maturities, amortized cost | $ 1,512,939 | $ 1,439,878 |
| Equity securities, cost | 65,913 | 68,812 |
| Short term investments, amortized cost | 0 | 2,541 |
| Agents' balances and premium receivable, allowance for doubtful accounts | 13,238 | 15,262 |
| Property and equipment, accumulated depreciation | 87,945 | 84,776 |
| Recoverable from reinsurers, paid losses and loss adjustment expenses | (3,124) | (1,269) |
| Long-term debt, fair value | $ 289,831 | $ 290,824 |
| Common stock, par value (usd per share) | $ 0 | $ 0 |
| Common stock, shares authorized (shares) | 50,000,000 | 50,000,000 |
| Common stock, shares issued (shares) | 21,879,505 | 21,867,436 |
| Treasury stock, shares (shares) | 10,937,569 | 10,932,539 |