• Filing Date: 2017-02-22
  • Form Type: 10-K
  • Description: Annual report
v3.6.0.2
Investments - Summary of Securities with Gross Unrealized Loss Positions Aggregated by Investment Category (Detail) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months $ (2,510) $ (5,690)
Fair Value, Less than Twelve Months 86,896 52,219
Gross Unrealized Loss, Twelve Months or Longer (379) (1,261)
Fair Value, Twelve Months or Longer 11,013 4,922
Gross Unrealized Loss, Total (2,889) (6,951)
Fair Value, Total 97,909 57,141
Equity Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (293) (1,350)
Fair Value, Less than Twelve Months 10,042 15,748
Gross Unrealized Loss, Twelve Months or Longer (191) (100)
Fair Value, Twelve Months or Longer 3,209 1,460
Gross Unrealized Loss, Total (484) (1,450)
Fair Value, Total 13,251 17,208
Fixed-Maturity Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (2,217) (4,340)
Fair Value, Less than Twelve Months 76,854 36,471
Gross Unrealized Loss, Twelve Months or Longer (188) (1,161)
Fair Value, Twelve Months or Longer 7,804 3,462
Gross Unrealized Loss, Total (2,405) (5,501)
Fair Value, Total 84,658 39,933
Fixed-Maturity Securities [Member] | U.S. Treasury and U.S. Government Agencies [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (36)  
Fair Value, Less than Twelve Months 1,939  
Gross Unrealized Loss, Total (36)  
Fair Value, Total 1,939  
Fixed-Maturity Securities [Member] | Corporate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (1,546) (3,667)
Fair Value, Less than Twelve Months 43,859 24,196
Gross Unrealized Loss, Twelve Months or Longer (95) (1,148)
Fair Value, Twelve Months or Longer 2,814 3,278
Gross Unrealized Loss, Total (1,641) (4,815)
Fair Value, Total 46,673 27,474
Fixed-Maturity Securities [Member] | State, Municipalities, and Political Subdivisions [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (441) (107)
Fair Value, Less than Twelve Months 26,029 6,587
Gross Unrealized Loss, Twelve Months or Longer (47) (13)
Fair Value, Twelve Months or Longer 3,036 184
Gross Unrealized Loss, Total (488) (120)
Fair Value, Total 29,065 6,771
Fixed-Maturity Securities [Member] | Exchange-Traded Debt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (191) (565)
Fair Value, Less than Twelve Months 4,980 5,559
Gross Unrealized Loss, Twelve Months or Longer (46)  
Fair Value, Twelve Months or Longer 1,954  
Gross Unrealized Loss, Total (237) (565)
Fair Value, Total 6,934 5,559
Fixed-Maturity Securities [Member] | Redeemable Preferred Stock [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (3) (1)
Fair Value, Less than Twelve Months 47 129
Gross Unrealized Loss, Total (3) (1)
Fair Value, Total $ 47 $ 129