Investments (Details - Maturity profile, securities purchased, sold and pledged assets) ([TradingSecuritiesMember], USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Payable/Receivable for Securites Purchased/Sold
Receivable for securities sold	$ 22,133,000	$ 71,477,000
Payable for securities purchased	32,944,000	86,557,000
Net (payable)/receivable for securities purchased/sold	(10,811,000)	(15,080,000)
Interest Rate Disclosures [Abstract]
Low end of interest rate on funds held	2.00%	2.00%	3.00%
High end of interest rate on funds held	5.00%	5.00%	6.00%
Pledged Assets
Restricted cash	167,500,000	21,300,000
Restricted securities	2,532,000,000	2,314,700,000
[CostMember]
Maturity Profile [Abstract]
One year or less	1,072,406,000
More than one year through five years	4,022,402,000
More than five years through ten years	3,999,711,000
More than ten years	815,927,000
Subtotal	9,910,446,000
Mortgage/asset-backed securities	3,893,803,000
Total	13,804,249,000
[FairValueMember]
Maturity Profile [Abstract]
One year or less	1,080,952,000
More than one year through five years	4,198,061,000
More than five years through ten years	4,336,243,000
More than ten years	941,117,000
Subtotal	10,556,373,000
Mortgage/asset-backed securities	3,989,494,000
Total	$ 14,545,867,000