Investments - Additional Information (Details) (USD $)
3 Months Ended
Mar. 31, 2015
MortgageLoan
instrument
security_issue
Mar. 31, 2014
MortgageLoan
instrument
Dec. 31, 2014
instrument
security_issue
Dec. 31, 2013
Investment Securities [Line Items]        
Derivative, Number of Instruments Held 0    0  
Additional review procedure performed, percent of amortized cost 90.00%      
Additional review procedure performed, percent of amortized cost, formal documentation prepared 80.00%      
Additional review procedure performed, decline in fair market value percent of amortized cost, formal documentation prepared, significant change in investments 10.00%      
Number of fixed maturities and equity securities below cost 72   96  
Other-than-temporary impairment losses on fixed maturity and equity securities $ 0 $ 213,000    
Percentage of invested assets in commercial mortgage loans 15.00%   15.00%  
Average loan to value ratio for overall portfolio 46.00%   46.00%  
Number of loans refinanced 3 2    
Amount of loans refinanced 4,500,000 3,200,000    
Maximum period of commits to fund commercial mortgage loans 120 days      
Net other-than-temporary impairment losses recognized in earnings 7,000 162,000    
Less than one year        
Investment Securities [Line Items]        
Number of fixed maturities and equity securities below cost 44   40  
One year or more and less than three years        
Investment Securities [Line Items]        
Number of fixed maturities and equity securities below cost 23   50  
Three years or more        
Investment Securities [Line Items]        
Number of fixed maturities and equity securities below cost 5   6  
Mortgage loans, net        
Investment Securities [Line Items]        
Allowance $ 1,923,000   1,914,000 $ 3,251,000