Separate Accounts - Additional Information (Details) (USD $)
Mar. 31, 2015
block
Dec. 31, 2014
Net Amount at Risk by Product and Guarantee [Line Items]    
Number of Blocks of Variable Universal Life Policies and Variable Annuity Contracts 2  
Separate account liabilities $ 412,357,000 $ 406,501,000
Separate account assets 412,357,000 406,501,000
Modified Coinsurance Transaction Separate Account Fund Balances 319,900,000 318,100,000
Future policy benefits 935,306,000 930,761,000
Guaranteed minimum withdrawal benefit    
Net Amount at Risk by Product and Guarantee [Line Items]    
Value of variable annuity separate accounts 131,300,000 132,300,000
Separate Accounts Guarantee Liability (2,800,000) (1,100,000)
Direct Block [Member]    
Net Amount at Risk by Product and Guarantee [Line Items]    
Future policy benefits 400,000 400,000
Assumed Block [Member]    
Net Amount at Risk by Product and Guarantee [Line Items]    
Future policy benefits $ 600,000 $ 600,000