Investments (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
Investments (Textual) [Abstract]
Fair value of issued securities	$ 6,398,442	[1]	$ 6,009,573	[1]
Investments (Additional Textual) [Abstract]
Cash received in an amount equal to fair value of securities transferred	95.00%
Fair value of securities transferred	50,616		24,791
Obligation for securities sold under agreement to repurchase, including accrued interest	49,245		25,864
Federal Home Loan Bank Funding Requirements	250,000		250,000
Federal Home Loan Bank [Member] | Fixed Maturities [Member]
Investments (Additional Textual) [Abstract]
Securities Deposited Fair Value	17,962		17,967
Securities Deposited As Collateral	275,034		274,437
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Investments (Textual) [Abstract]
Fair value of issued securities	343,090		336,193
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Investments (Textual) [Abstract]
Fair value of issued securities	434,214		427,172
Government National Mortgage Association Certificates and Obligations (GNMA) [Member]
Investments (Textual) [Abstract]
Fair value of issued securities	$ 132,896		$ 126,245

[1] Fair value includes securities issued by Federal National Mortgage Association (“FNMA”) of $343,090 and $336,193; Federal Home Loan Mortgage Corporation (“FHLMC”) of $434,214 and $427,172; and Government National Mortgage Association (“GNMA”) of $132,896 and $126,245 as of March 31, 2014 and December 31, 2013, respectively.