Investment Information (Text Items) (Details) (USD $)	Mar. 31, 2013 lots	Dec. 31, 2012 lots
Continuous unrealized loss, qualitative disclosures:
Number of positions in an unrealized loss position (lots)	860	910
Total number of positions (lots)	4,340	4,580
Largest single loss	$ 3,200,000	$ 2,500,000
Securities lending, qualitative disclosures:
Fair value of fixed maturities and short-term investments pledged under securities lending agreements	90,800,000	50,800,000
Amortized cost of fixed maturities and short-term investments pledged under securities lending agreements	88,400,000	49,600,000
Fair value of securities backing securities lending program	84,315,000	42,531,000
Approximate fair value of sub-prime securities backing the securities lending program	$ 5,400,000	$ 5,400,000