Investments - Aging of Gross Unrealized Investment Losses (Detail) (USD $) | Mar. 31, 2015 | Dec. 31, 2014 |
In Thousands, unless otherwise specified | Security | Security |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 397 | 214 |
Gross Unrealized Losses, Less Than Twelve Months | $1,693 | $1,527 |
Fair Value, Less Than Twelve Months | 83,585 | 111,109 |
Number of Securities, Twelve Months or Greater | 21 | 27 |
Gross Unrealized Losses, Twelve Months or Greater | 29 | 114 |
Fair Value, Twelve Months or Greater | 1,521 | 4,698 |
Fixed Maturities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 161 | 212 |
Gross Unrealized Losses, Less Than Twelve Months | 318 | 457 |
Fair Value, Less Than Twelve Months | 72,054 | 98,765 |
Number of Securities, Twelve Months or Greater | 15 | 26 |
Gross Unrealized Losses, Twelve Months or Greater | 21 | 92 |
Fair Value, Twelve Months or Greater | 1,346 | 4,208 |
Equity Securities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 236 | 2 |
Gross Unrealized Losses, Less Than Twelve Months | 1,375 | 1,070 |
Fair Value, Less Than Twelve Months | 11,531 | 12,344 |
Number of Securities, Twelve Months or Greater | 6 | 1 |
Gross Unrealized Losses, Twelve Months or Greater | 8 | 22 |
Fair Value, Twelve Months or Greater | 175 | 490 |
U.S. Government and Agency Securities [Member] | Fixed Maturities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 5 | 11 |
Gross Unrealized Losses, Less Than Twelve Months | 32 | 15 |
Fair Value, Less Than Twelve Months | 4,034 | 2,451 |
Number of Securities, Twelve Months or Greater | | 1 |
Gross Unrealized Losses, Twelve Months or Greater | | 1 |
Fair Value, Twelve Months or Greater | | 109 |
States, Municipalities and Political Subdivisions [Member] | Fixed Maturities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 20 | 14 |
Gross Unrealized Losses, Less Than Twelve Months | 50 | 15 |
Fair Value, Less Than Twelve Months | 13,159 | 7,661 |
Number of Securities, Twelve Months or Greater | 1 | 1 |
Gross Unrealized Losses, Twelve Months or Greater | 3 | 3 |
Fair Value, Twelve Months or Greater | 169 | 177 |
Industrial And Commercial Bank Of China Financial Services Llc [Member] | Fixed Maturities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 35 | 98 |
Gross Unrealized Losses, Less Than Twelve Months | 32 | 204 |
Fair Value, Less Than Twelve Months | 15,260 | 51,156 |
Number of Securities, Twelve Months or Greater | 5 | 10 |
Gross Unrealized Losses, Twelve Months or Greater | 12 | 50 |
Fair Value, Twelve Months or Greater | 733 | 1,975 |
Special Revenue [Member] | Fixed Maturities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 67 | 71 |
Gross Unrealized Losses, Less Than Twelve Months | 200 | 213 |
Fair Value, Less Than Twelve Months | 39,172 | 36,643 |
Number of Securities, Twelve Months or Greater | 2 | 6 |
Gross Unrealized Losses, Twelve Months or Greater | 3 | 23 |
Fair Value, Twelve Months or Greater | 340 | 1,592 |
Redeemable Preferred Stocks [Member] | Fixed Maturities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 34 | 18 |
Gross Unrealized Losses, Less Than Twelve Months | 4 | 9 |
Fair Value, Less Than Twelve Months | 429 | 854 |
Number of Securities, Twelve Months or Greater | 7 | 9 |
Gross Unrealized Losses, Twelve Months or Greater | 3 | 15 |
Fair Value, Twelve Months or Greater | 104 | 355 |
Nonredeemable Preferred Stocks [Member] | Equity Securities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 78 | 1 |
Gross Unrealized Losses, Less Than Twelve Months | 20 | 31 |
Fair Value, Less Than Twelve Months | 1,454 | 2,552 |
Number of Securities, Twelve Months or Greater | 6 | 1 |
Gross Unrealized Losses, Twelve Months or Greater | 8 | 22 |
Fair Value, Twelve Months or Greater | 175 | 490 |
Equity Investment [Member] | Equity Securities [Member] | | |
Schedule Of Fair Value And Gross Unrealized Losses [Line Items] | | |
Number of Securities, Less Than Twelve Months | 158 | 1 |
Gross Unrealized Losses, Less Than Twelve Months | 1,355 | 1,039 |
Fair Value, Less Than Twelve Months | $10,077 | $9,792 |