Investments (Details Textual) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Investments (Textual) [Abstract]
Fair value of issued securities	$ 6,793,469	$ 6,009,573
Investments (Additional Textual) [Abstract]
Cash received in an amount equal to fair value of securities transferred	95.00%
Fair value of securities transferred	0	24,791
Obligation for securities sold under agreement to repurchase, including accrued interest	0	25,864
Federal Home Loan Bank Funding Requirements	500,000	250,000
Investment Grade Rate	87.00%
Federal Home Loan Bank [Member] | Fixed Maturities [Member]
Investments (Additional Textual) [Abstract]
Securities Deposited Fair Value	18,338	17,967
Securities Deposited As Collateral	551,451	274,437
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Investments (Textual) [Abstract]
Fair value of issued securities	319,596	336,193
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Investments (Textual) [Abstract]
Fair value of issued securities	419,913	427,172
Government National Mortgage Association Certificates and Obligations (GNMA) [Member]
Investments (Textual) [Abstract]
Fair value of issued securities	$ 136,379	$ 126,245