Fair Value Measurements - Financial instruments not carried at fair value (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, held to maturity	$ 0	$ 2,858,695
Other investments - structured transactions	276,200	294,000
Deposit liabilities	1,242,696	1,509,243
Notes payable and debt	1,662,206	2,263,203
Fair value of held to maturity securities	0	3,131,235
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, held to maturity	0	2,858,695
Other investments - structured transactions	276,172	294,048
Financial Assets	276,172	3,152,743
Deposit liabilities	1,242,696	1,509,243
Notes payable and debt	1,662,206	2,263,203
Financial Liabilities	2,904,902	3,772,446
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, held to maturity	0	3,131,235
Other investments - structured transactions	299,216	296,799
Financial Assets	299,216	3,428,034
Deposit liabilities	1,495,346	1,718,394
Notes payable and debt	1,880,124	2,429,412
Financial Liabilities	$ 3,375,470	$ 4,147,806