Investments (Details) (USD $) | 3 Months Ended | 6 Months Ended | 12 Months Ended |
In Thousands, unless otherwise specified | Jun. 30, 2014 | Jun. 30, 2013 | Jun. 30, 2014 | Jun. 30, 2013 | Dec. 31, 2013 |
| Security | Security | Security |
| Agreement | Agreement | |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Cost or amortized cost | $426,178 | ' | $426,178 | ' | ' |
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Applicable federal income taxes | -31,979 | ' | ' | ' | -26,432 |
Net unrealized gains - net of tax | 59,389 | ' | ' | ' | 49,089 |
Available-for-sale securities continuous unrealized loss position [Abstract] | ' | ' | ' | ' | ' |
Number of Securities, total | 356 | ' | 356 | ' | 516 |
Available-for-sale securities continuous unrealized loss position, Fair Value [Abstract] | ' | ' | ' | ' | ' |
Fair value, total | 96,053 | ' | 96,053 | ' | 145,056 |
Available-for-sale securities continuous unrealized loss position, aggregate losses [Abstract] | ' | ' | ' | ' | ' |
Gross unrealized loss, total | ' | ' | -3,128 | ' | -4,584 |
Available-for-sale securities debt maturities fair value [Abstract] | ' | ' | ' | ' | ' |
One year or less, Fair Value | 124,351 | ' | 124,351 | ' | ' |
Excess of one year to five years, Fair Value | 165,938 | ' | 165,938 | ' | ' |
Excess of five years to ten years, Fair Value | 62,049 | ' | 62,049 | ' | ' |
Excess of ten years, Fair Value | 8,076 | ' | 8,076 | ' | ' |
Contractual maturities, Fair Value | 360,414 | ' | 360,414 | ' | ' |
Asset-backed securities, Fair Value | 69,046 | ' | 69,046 | ' | ' |
Total, Fair Value | 429,460 | ' | 429,460 | ' | ' |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' | ' | ' |
One year or less, Amortized Cost Basis | 124,042 | ' | 124,042 | ' | ' |
Excess of one year to five years, Amortized Cost Basis | 165,905 | ' | 165,905 | ' | ' |
Excess of five years to ten years, Amortized Cost Basis | 60,694 | ' | 60,694 | ' | ' |
Excess of ten years, Amortized Cost Basis | 7,347 | ' | 7,347 | ' | ' |
Contractual maturities, Amortized Cost Basis | 357,988 | ' | 357,988 | ' | ' |
Asset-backed securities, Amortized Cost Basis | 68,190 | ' | 68,190 | ' | ' |
Cost or amortized cost | 426,178 | ' | 426,178 | ' | ' |
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract] | ' | ' | ' | ' | ' |
Limited partnerships - net gain (loss) | 5,200 | -1,275 | 8,268 | 2,438 | ' |
Net realized gains on investments | 8,089 | 719 | 12,159 | 15,066 | ' |
Available for sale securities gain loss activity [Abstract] | ' | ' | ' | ' | ' |
Realized net gains on the disposal of securities | 2,419 | 1,554 | 3,614 | 10,798 | ' |
Mark-to-market adjustment | 469 | 195 | 269 | 405 | ' |
Equity in gains of limited partnership investments - realized and unrealized | 5,200 | -1,275 | 8,268 | 2,438 | ' |
Write-downs based upon objective criteria | 0 | -68 | -105 | -74 | ' |
Recovery of prior write-downs upon sale or disposal | 1 | 313 | 113 | 1,499 | ' |
Net realized gains on investments | 8,089 | 719 | 12,159 | 15,066 | ' |
Net unrealized gain (loss) on investments | 1,649 | ' | 5,507 | ' | ' |
Net unrealized gains in limited partnership | ' | ' | 12,971 | ' | ' |
Undistributed earnings of limited partnership, net of taxes | 29,768 | ' | 29,768 | ' | ' |
Committed funds for bridge loans | 64,750 | ' | 64,750 | ' | ' |
Number of bridge loan agreements | 7 | ' | 7 | ' | ' |
U.S. government obligations [Member] | ' | ' | ' | ' | ' |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 119,517 | ' | 119,517 | ' | 113,389 |
Cost or amortized cost | 119,356 | ' | 119,356 | ' | 113,348 |
Gross unrealized gains | 176 | ' | 176 | ' | 81 |
Gross unrealized losses | -15 | ' | -15 | ' | -40 |
Net unrealized gains (losses) | 161 | ' | 161 | ' | 41 |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' | ' | ' |
Cost or amortized cost | 119,356 | ' | 119,356 | ' | 113,348 |
Residential mortgage-backed securities [Member] | ' | ' | ' | ' | ' |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 7,935 | ' | 7,935 | ' | 13,252 |
Cost or amortized cost | 7,574 | ' | 7,574 | ' | 12,058 |
Gross unrealized gains | 424 | ' | 424 | ' | 1,334 |
Gross unrealized losses | -63 | ' | -63 | ' | -140 |
Net unrealized gains (losses) | 361 | ' | 361 | ' | 1,194 |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' | ' | ' |
Cost or amortized cost | 7,574 | ' | 7,574 | ' | 12,058 |
Commercial mortgage-backed securities [Member] | ' | ' | ' | ' | ' |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 26,618 | ' | 26,618 | ' | 28,565 |
Cost or amortized cost | 25,878 | ' | 25,878 | ' | 28,406 |
Gross unrealized gains | 815 | ' | 815 | ' | 308 |
Gross unrealized losses | -75 | ' | -75 | ' | -149 |
Net unrealized gains (losses) | 740 | ' | 740 | ' | 159 |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' | ' | ' |
Cost or amortized cost | 25,878 | ' | 25,878 | ' | 28,406 |
States and municipal obligations [Member] | ' | ' | ' | ' | ' |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 114,212 | ' | 114,212 | ' | 115,250 |
Cost or amortized cost | 113,481 | ' | 113,481 | ' | 115,278 |
Gross unrealized gains | 861 | ' | 861 | ' | 407 |
Gross unrealized losses | -130 | ' | -130 | ' | -435 |
Net unrealized gains (losses) | 731 | ' | 731 | ' | -28 |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' | ' | ' |
Cost or amortized cost | 113,481 | ' | 113,481 | ' | 115,278 |
Corporate securities [Member] | ' | ' | ' | ' | ' |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 135,435 | ' | 135,435 | ' | 137,215 |
Cost or amortized cost | 134,469 | ' | 134,469 | ' | 136,991 |
Gross unrealized gains | 3,426 | ' | 3,426 | ' | 3,207 |
Gross unrealized losses | -2,460 | ' | -2,460 | ' | -2,983 |
Net unrealized gains (losses) | 966 | ' | 966 | ' | 224 |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' | ' | ' |
Cost or amortized cost | 134,469 | ' | 134,469 | ' | 136,991 |
Foreign government obligations [Member] | ' | ' | ' | ' | ' |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 25,743 | ' | 25,743 | ' | 23,879 |
Cost or amortized cost | 25,420 | ' | 25,420 | ' | 23,689 |
Gross unrealized gains | 471 | ' | 471 | ' | 588 |
Gross unrealized losses | -148 | ' | -148 | ' | -398 |
Net unrealized gains (losses) | 323 | ' | 323 | ' | 190 |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' | ' | ' |
Cost or amortized cost | 25,420 | ' | 25,420 | ' | 23,689 |
Total fixed maturities [Member] | ' | ' | ' | ' | ' |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 429,460 | ' | 429,460 | ' | 431,550 |
Cost or amortized cost | 426,178 | ' | 426,178 | ' | 429,770 |
Gross unrealized gains | 6,173 | ' | 6,173 | ' | 5,925 |
Gross unrealized losses | -2,891 | ' | -2,891 | ' | -4,145 |
Net unrealized gains (losses) | 3,282 | ' | 3,282 | ' | 1,780 |
Available-for-sale securities continuous unrealized loss position [Abstract] | ' | ' | ' | ' | ' |
Number of Securities Less than 12 months | 256 | ' | 256 | ' | 451 |
Number of Securities More than 12 months | 86 | ' | 86 | ' | 53 |
Number of Securities, total | 342 | ' | 342 | ' | 504 |
Available-for-sale securities continuous unrealized loss position, Fair Value [Abstract] | ' | ' | ' | ' | ' |
Fair value, 12 months or less | 61,528 | ' | 61,528 | ' | 123,145 |
Fair value, 12 months or longer | 30,389 | ' | 30,389 | ' | 18,249 |
Fair value, total | 91,917 | ' | 91,917 | ' | 141,394 |
Available-for-sale securities continuous unrealized loss position, aggregate losses [Abstract] | ' | ' | ' | ' | ' |
Gross unrealized loss, less than 12 months | ' | ' | -1,827 | ' | -3,105 |
Gross unrealized loss, 12 months or longer | ' | ' | -1,064 | ' | -1,040 |
Gross unrealized loss, total | ' | ' | -2,891 | ' | -4,145 |
Available-for-sale securities debt maturities amortized cost basis [Abstract] | ' | ' | ' | ' | ' |
Cost or amortized cost | 426,178 | ' | 426,178 | ' | 429,770 |
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract] | ' | ' | ' | ' | ' |
Gross gains | 2,762 | 2,233 | 4,601 | 3,652 | ' |
Gross losses | -926 | -883 | -2,152 | -2,220 | ' |
Net realized gains | 1,836 | 1,350 | 2,449 | 1,432 | ' |
Financial institutions [Member] | ' | ' | ' | ' | ' |
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 20,456 | ' | 20,456 | ' | 18,850 |
Cost or amortized cost | 8,565 | ' | 8,565 | ' | 7,780 |
Gross unrealized gains | 11,907 | ' | 11,907 | ' | 11,171 |
Gross unrealized losses | -16 | ' | -16 | ' | -101 |
Net unrealized gains (losses) | 11,891 | ' | 11,891 | ' | 11,070 |
Industrial & miscellaneous [Member] | ' | ' | ' | ' | ' |
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 140,470 | ' | 140,470 | ' | 126,978 |
Cost or amortized cost | 64,275 | ' | 64,275 | ' | 64,307 |
Gross unrealized gains | 76,416 | ' | 76,416 | ' | 63,009 |
Gross unrealized losses | -221 | ' | -221 | ' | -338 |
Net unrealized gains (losses) | 76,195 | ' | 76,195 | ' | 62,671 |
Total equity securities [Member] | ' | ' | ' | ' | ' |
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 160,926 | ' | 160,926 | ' | 145,828 |
Cost or amortized cost | 72,840 | ' | 72,840 | ' | 72,087 |
Gross unrealized gains | 88,323 | ' | 88,323 | ' | 74,180 |
Gross unrealized losses | -237 | ' | -237 | ' | -439 |
Net unrealized gains (losses) | 88,086 | ' | 88,086 | ' | 73,741 |
Available-for-sale securities continuous unrealized loss position [Abstract] | ' | ' | ' | ' | ' |
Number of Securities Less than 12 months | 10 | ' | 10 | ' | 10 |
Number of Securities More than 12 months | 4 | ' | 4 | ' | 2 |
Number of Securities, total | 14 | ' | 14 | ' | 12 |
Available-for-sale securities continuous unrealized loss position, Fair Value [Abstract] | ' | ' | ' | ' | ' |
Fair value, 12 months or less | 3,510 | ' | 3,510 | ' | 1,682 |
Fair value, 12 months or longer | 626 | ' | 626 | ' | 1,980 |
Fair value, total | 4,136 | ' | 4,136 | ' | 3,662 |
Available-for-sale securities continuous unrealized loss position, aggregate losses [Abstract] | ' | ' | ' | ' | ' |
Gross unrealized loss, less than 12 months | ' | ' | -185 | ' | -204 |
Gross unrealized loss, 12 months or longer | ' | ' | -52 | ' | -235 |
Gross unrealized loss, total | ' | ' | -237 | ' | -439 |
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract] | ' | ' | ' | ' | ' |
Gross gains | 1,412 | 893 | 2,153 | 12,605 | ' |
Gross losses | -359 | -249 | -711 | -1,409 | ' |
Net realized gains | 1,053 | 644 | 1,442 | 11,196 | ' |
Total available-for-sale securities [Member] | ' | ' | ' | ' | ' |
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract] | ' | ' | ' | ' | ' |
Fair value | 590,386 | ' | 590,386 | ' | 577,378 |
Cost or amortized cost | 499,018 | ' | 499,018 | ' | 501,857 |
Gross unrealized gains | 94,496 | ' | 94,496 | ' | 80,105 |
Gross unrealized losses | -3,128 | ' | -3,128 | ' | -4,584 |
Net unrealized gains (losses) | $91,368 | ' | $91,368 | ' | $75,521 |