Note 7 - Investments Investments In Any Person And Its Affiliates That Exceed 10% of Total Stockholders' Equity (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Investment Holdings [Line Items]
Trading Securities	$ 4,094,622,000	$ 4,211,059,000
Short-term Investments	777,532,000	1,261,703,000
Total	5,152,418,000	5,783,559,000
Available-for-sale Securities, Equity Securities	112,139,000	128,424,000
Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Trading Securities	543,050,000
Short-term Investments	638,046,000
Total	1,375,042,000
Other invested assets fair value disclosure	78,006,000
Marketable Securities, Fixed Maturities	6,272,000
Available-for-sale Securities, Equity Securities	109,668,000
Debt Securities
Investment Holdings [Line Items]
Assets Held by Insurance Regulators	18,000,000	21,100,000
Funds Held under Reinsurance Agreements, Asset	172,600,000	116,400,000
Northern Institutional Treasury Portfolio [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Trading Securities	0
Short-term Investments	258,560,000
Total	258,560,000
State of Illinois [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Trading Securities	138,414,000
Short-term Investments	0
Total	138,414,000
Citigroup Inc Corporate And Direct Affiliate Obligors [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Trading Securities	131,405,000
Short-term Investments	0
Total	134,507,000
Marketable Securities, Fixed Maturities	3,102,000
BlackRock Liquidity Funds T-Fund Money Market [Member] [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Trading Securities	0
Short-term Investments	133,391,000
Total	133,391,000
Bank of America Corp [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Trading Securities	100,499,000
Short-term Investments	0
Total	114,424,000
Marketable Securities, Fixed Maturities	3,170,000
Available-for-sale Securities, Equity Securities	10,755,000
Vanguard Institutional Index Fund [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Total	98,913,000
Available-for-sale Securities, Equity Securities	98,913,000
State Of California [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Trading Securities	91,269,000
Total	91,269,000
STIT Treasury Portfolio Cash Management Fund [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Short-term Investments	84,018,000
Total	84,018,000
Federated Treasury Obligations Fund [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Short-term Investments	81,507,000
Total	81,507,000
Wells Fargo and Company [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Trading Securities	81,463,000
Total	81,463,000
Fidelity Institutional Treasury Only Portfolio [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Short-term Investments	80,570,000
Total	80,570,000
The Royal Bank of Scotland Group plc [Member] | Investments in Any Person and Its Affiliates That Exceed 10 Percent of Total Stockholders Equity [Member]
Investment Holdings [Line Items]
Total	78,006,000
Other invested assets fair value disclosure	$ 78,006,000