Investments (Details) (USD $) | 3 Months Ended | 12 Months Ended |
In Thousands, unless otherwise specified | Mar. 31, 2014 | Mar. 31, 2013 | Dec. 31, 2013 |
| Security | Security |
| Agreement | |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Applicable federal income taxes | ($29,224) | ' | ($26,432) |
Net unrealized gains - net of tax | 54,272 | ' | 49,089 |
Available-for-sale securities continuous unrealized loss position [Abstract] | ' | ' | ' |
Number of Securities, total | 451 | ' | 516 |
Available-for-sale securities continuous unrealized loss position, Fair Value [Abstract] | ' | ' | ' |
Fair value, total | 133,217 | ' | 145,056 |
Available-for-sale securities continuous unrealized loss position, aggregate losses [Abstract] | ' | ' | ' |
Gross unrealized loss, total | -3,591 | ' | -4,584 |
Available-for-sale securities debt maturities fair value [Abstract] | ' | ' | ' |
One year or less, Fair Value | 98,307 | ' | ' |
Excess of one year to five years, Fair Value | 193,827 | ' | ' |
Excess of five years to ten years, Fair Value | 56,991 | ' | ' |
Excess of ten years, Fair Value | 7,891 | ' | ' |
Contractual maturities, Fair Value | 357,016 | ' | ' |
Asset-backed securities, Fair Value | 77,026 | ' | ' |
Total, Fair Value | 434,042 | ' | ' |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' |
One year or less, Amortized Cost Basis | 98,690 | ' | ' |
Excess of one year to five years, Amortized Cost Basis | 193,119 | ' | ' |
Excess of five years to ten years, Amortized Cost Basis | 56,364 | ' | ' |
Excess of ten years, Amortized Cost Basis | 7,232 | ' | ' |
Contractual maturities, Amortized Cost Basis | 355,405 | ' | ' |
Asset-backed securities, Amortized Cost Basis | 75,551 | ' | ' |
Total, Amortized cost basis | 430,956 | ' | ' |
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract] | ' | ' | ' |
Limited partnerships - net gain | 3,068 | 3,713 | ' |
Totals | 4,070 | 14,347 | ' |
Available for sale securities gain loss activity [Abstract] | ' | ' | ' |
Realized net gains on the disposal of securities | 1,195 | 9,244 | ' |
Mark-to-market adjustment | -200 | 210 | ' |
Equity in gains of limited partnership investments - realized and unrealized | 3,068 | 3,713 | ' |
Write-downs based upon objective criteria | -105 | -6 | ' |
Recovery of prior write-downs upon sale or disposal | 112 | 1,186 | ' |
Totals | 4,070 | 14,347 | ' |
Net unrealized gain (loss) on investments | 3,859 | ' | ' |
Net unrealized gains in limited partnership | 11,322 | ' | ' |
Undistributed earnings of limited partnership, net of taxes | 26,455 | ' | ' |
Committed funds for bridge loans | 20,000 | ' | ' |
Number of bridge loan agreements | 3 | ' | ' |
U.S. government obligations [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 121,426 | ' | 113,389 |
Cost or Amortized Cost | 121,413 | ' | 113,348 |
Gross Unrealized Gains | 117 | ' | 81 |
Gross Unrealized Losses | -104 | ' | -40 |
Net Unrealized Gains (Losses) | 13 | ' | 41 |
Residential mortgage-backed securities [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 16,741 | ' | 13,252 |
Cost or Amortized Cost | 15,302 | ' | 12,058 |
Gross Unrealized Gains | 1,520 | ' | 1,334 |
Gross Unrealized Losses | -81 | ' | -140 |
Net Unrealized Gains (Losses) | 1,439 | ' | 1,194 |
Commercial mortgage-backed securities [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 25,561 | ' | 28,565 |
Cost or Amortized Cost | 25,217 | ' | 28,406 |
Gross Unrealized Gains | 479 | ' | 308 |
Gross Unrealized Losses | -135 | ' | -149 |
Net Unrealized Gains (Losses) | 344 | ' | 159 |
States and municipal obligations [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 115,378 | ' | 115,250 |
Cost or Amortized Cost | 115,054 | ' | 115,278 |
Gross Unrealized Gains | 617 | ' | 407 |
Gross Unrealized Losses | -293 | ' | -435 |
Net Unrealized Gains (Losses) | 324 | ' | -28 |
Corporate securities [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 127,715 | ' | 137,215 |
Cost or Amortized Cost | 126,937 | ' | 136,991 |
Gross Unrealized Gains | 3,255 | ' | 3,207 |
Gross Unrealized Losses | -2,477 | ' | -2,983 |
Net Unrealized Gains (Losses) | 778 | ' | 224 |
Foreign government obligations [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 27,221 | ' | 23,879 |
Cost or Amortized Cost | 27,033 | ' | 23,689 |
Gross Unrealized Gains | 467 | ' | 588 |
Gross Unrealized Losses | -279 | ' | -398 |
Net Unrealized Gains (Losses) | 188 | ' | 190 |
Total fixed maturities [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 434,042 | ' | 431,550 |
Cost or Amortized Cost | 430,956 | ' | 429,770 |
Gross Unrealized Gains | 6,455 | ' | 5,925 |
Gross Unrealized Losses | -3,369 | ' | -4,145 |
Net Unrealized Gains (Losses) | 3,086 | ' | 1,780 |
Available-for-sale securities continuous unrealized loss position [Abstract] | ' | ' | ' |
Number of Securities Less than 12 months | 369 | ' | 451 |
Number of Securities More than 12 months | 69 | ' | 53 |
Number of Securities, total | 438 | ' | 504 |
Available-for-sale securities continuous unrealized loss position, Fair Value [Abstract] | ' | ' | ' |
Fair value, 12 months or less | 114,779 | ' | 123,145 |
Fair value, 12 months or longer | 16,018 | ' | 18,249 |
Fair value, total | 130,797 | ' | 141,394 |
Available-for-sale securities continuous unrealized loss position, aggregate losses [Abstract] | ' | ' | ' |
Gross unrealized loss, less than 12 months | -2,339 | ' | -3,105 |
Gross unrealized loss, 12 months or longer | -1,030 | ' | -1,040 |
Gross unrealized loss, total | -3,369 | ' | -4,145 |
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract] | ' | ' | ' |
Gross gains | 1,839 | 1,419 | ' |
Gross losses | -1,226 | -1,337 | ' |
Net realized gains | 613 | 82 | ' |
Financial institutions [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 19,376 | ' | 18,850 |
Cost or Amortized Cost | 7,770 | ' | 7,780 |
Gross Unrealized Gains | 11,606 | ' | 11,171 |
Gross Unrealized Losses | 0 | ' | -101 |
Net Unrealized Gains (Losses) | 11,606 | ' | 11,070 |
Industrial & Miscellaneous [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 133,453 | ' | 126,978 |
Cost or Amortized Cost | 64,649 | ' | 64,307 |
Gross Unrealized Gains | 69,026 | ' | 63,009 |
Gross Unrealized Losses | -222 | ' | -338 |
Net Unrealized Gains (Losses) | 68,804 | ' | 62,671 |
Total equity securities [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 152,829 | ' | 145,828 |
Cost or Amortized Cost | 72,419 | ' | 72,087 |
Gross Unrealized Gains | 80,632 | ' | 74,180 |
Gross Unrealized Losses | -222 | ' | -439 |
Net Unrealized Gains (Losses) | 80,410 | ' | 73,741 |
Available-for-sale securities continuous unrealized loss position [Abstract] | ' | ' | ' |
Number of Securities Less than 12 months | 12 | ' | 10 |
Number of Securities More than 12 months | 1 | ' | 2 |
Number of Securities, total | 13 | ' | 12 |
Available-for-sale securities continuous unrealized loss position, Fair Value [Abstract] | ' | ' | ' |
Fair value, 12 months or less | 2,401 | ' | 1,682 |
Fair value, 12 months or longer | 19 | ' | 1,980 |
Fair value, total | 2,420 | ' | 3,662 |
Available-for-sale securities continuous unrealized loss position, aggregate losses [Abstract] | ' | ' | ' |
Gross unrealized loss, less than 12 months | -221 | ' | -204 |
Gross unrealized loss, 12 months or longer | -1 | ' | -235 |
Gross unrealized loss, total | -222 | ' | -439 |
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract] | ' | ' | ' |
Gross gains | 741 | 11,712 | ' |
Gross losses | -352 | -1,160 | ' |
Net realized gains | 389 | 10,552 | ' |
Total available-for-sale securities [Member] | ' | ' | ' |
Schedule of Available-For-Sale Securities [Line Items] | ' | ' | ' |
Fair Value | 586,871 | ' | 577,378 |
Cost or Amortized Cost | 503,375 | ' | 501,857 |
Gross Unrealized Gains | 87,087 | ' | 80,105 |
Gross Unrealized Losses | -3,591 | ' | -4,584 |
Net Unrealized Gains (Losses) | $83,496 | ' | $75,521 |