Investments (Details 10)	Jun. 30, 2011	Dec. 31, 2010
NAIC 1 [Member]
NAIC rating distribution of the Company's holdings of CMBS
NAIC ratings distribution of CMBS	94.10%	93.70%
NAIC 2 [Member]
NAIC rating distribution of the Company's holdings of CMBS
NAIC ratings distribution of CMBS	3.70%	3.20%
NAIC 3 [Member]
NAIC rating distribution of the Company's holdings of CMBS
NAIC ratings distribution of CMBS	1.20%	1.80%
NAIC 4 [Member]
NAIC rating distribution of the Company's holdings of CMBS
NAIC ratings distribution of CMBS	0.90%	1.00%
NAIC 5 [Member]
NAIC rating distribution of the Company's holdings of CMBS
NAIC ratings distribution of CMBS	0.10%	0.30%
NAIC 6 [Member]
NAIC rating distribution of the Company's holdings of CMBS
NAIC ratings distribution of CMBS	0.00%	0.00%