Fair Value of Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investments
Other investments, Carrying Amount	$ 6,340,752	$ 6,292,097
Financial Liabilities
Fixed annuity contract liabilities, Carrying Amount	3,454,356	3,257,758
Fixed annuity contract liabilities, Fair value	3,254,859	3,070,111
Policyholder account balances on interest-sensitive life contracts, Carrying Amount	78,843	79,017
Policyholder account balances on interest-sensitive life contracts, Fair value	78,345	78,519
Other policyholder funds, Carrying Amount	97,823	103,227
Other policyholder funds, Fair Value	97,823	103,227
Short-term debt, Carrying Amount	38,000	38,000
Short-term debt, Fair Value	38,000	38,000
Long-term debt, Carrying Amount	199,858	199,809
Long-term debt, Fair Value	215,918	219,319
Other liabilities, repurchase agreement obligations, Carrying Amount	121,308
Other liabilities, repurchase agreement obligations, Fair Value	121,308
Other investments [Member]
Investments
Other investments, Carrying Amount	139,010	134,985
Other investments, Fair Value	144,054	135,121
Level 1 [Member]
Financial Liabilities
Fixed annuity contract liabilities, Fair value	0	0
Policyholder account balances on interest-sensitive life contracts, Fair value	0	0
Other policyholder funds, Fair Value	0	0
Short-term debt, Fair Value	0	0
Long-term debt, Fair Value	215,918	219,319
Other liabilities, repurchase agreement obligations, Carrying Amount	0
Level 1 [Member] | Other investments [Member]
Investments
Other investments, Fair Value	0	0
Level 2 [Member]
Financial Liabilities
Fixed annuity contract liabilities, Fair value	0	0
Policyholder account balances on interest-sensitive life contracts, Fair value	0	0
Other policyholder funds, Fair Value	0	0
Short-term debt, Fair Value	38,000	38,000
Long-term debt, Fair Value	0	0
Other liabilities, repurchase agreement obligations, Carrying Amount	121,308
Level 2 [Member] | Other investments [Member]
Investments
Other investments, Fair Value	0	0
Level 3 [Member]
Financial Liabilities
Fixed annuity contract liabilities, Fair value	3,254,859	3,070,111
Policyholder account balances on interest-sensitive life contracts, Fair value	78,345	78,519
Other policyholder funds, Fair Value	97,823	103,227
Short-term debt, Fair Value	0	0
Long-term debt, Fair Value	0	0
Other liabilities, repurchase agreement obligations, Carrying Amount	0
Level 3 [Member] | Other investments [Member]
Investments
Other investments, Fair Value	$ 144,054	$ 135,121