Note 19 - Quarterly Financial Data (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended			3 Months Ended																12 Months Ended
	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Quarterly Financial Data (Unaudited) [Member]		Sep. 30, 2011 Quarterly Financial Data (Unaudited) [Member]		Jun. 30, 2011 Quarterly Financial Data (Unaudited) [Member]		Mar. 31, 2011 Quarterly Financial Data (Unaudited) [Member]		Dec. 31, 2010 Quarterly Financial Data (Unaudited) [Member]		Sep. 30, 2010 Quarterly Financial Data (Unaudited) [Member]		Jun. 30, 2010 Quarterly Financial Data (Unaudited) [Member]		Mar. 31, 2010 Quarterly Financial Data (Unaudited) [Member]		Dec. 31, 2011 Quarterly Financial Data (Unaudited) [Member]		Dec. 31, 2010 Quarterly Financial Data (Unaudited) [Member]
Net premiums earned-insurance		$ 756,025,000	$ 825,733,000	$ 825,901,000	$ 184,413,000		$ 179,655,000		$ 188,934,000		$ 203,023,000		$ 220,082,000		$ 203,937,000		$ 203,446,000		$ 198,268,000		$ 756,025,000		$ 825,733,000
Net investment income		163,520,000	178,760,000	214,190,000	38,694,000		38,763,000		43,823,000		42,240,000		38,229,000		46,554,000		48,619,000		45,358,000		163,520,000		178,760,000
Gain (Loss) on Investments		202,177,000	139,944,000	257,141,000	38,866,000	[1]	81,640,000	[1]	44,236,000	[1]	37,435,000	[1]	(69,524,000)	[1]	94,258,000	[1]	57,262,000	[1]	57,948,000	[1]	202,177,000	[1]	139,944,000	[1]
Net impairment losses recognized in earnings		(1,202,000)	(90,000)	(9,269,000)	(1,171,000)		(20,000)		(11,000)		0		0		(34,000)		(38,000)		(18,000)		(1,202,000)		(90,000)
Change in fair value of derivative instruments		628,395,000	(558,712,000)	99,958,000	69,769,000	[2]	126,008,000	[2]	188,726,000	[2]	243,892,000	[2]	(185,935,000)	[2]	229,783,000	[2]	(524,606,000)	[2]	(77,954,000)	[2]	628,395,000	[2]	(558,712,000)	[2]
Net gains (losses) on other financial instruments		193,329,000	(211,681,000)	(88,569,000)	32,429,000	[3]	80,602,000	[3]	5,047,000	[3]	75,251,000	[3]	(51,799,000)	[3]	4,882,000	[3]	(63,200,000)	[3]	(101,564,000)	[3]	193,329,000	[3]	(211,681,000)	[3]
Gain on sale of affiliate		0	34,815,000	0									0		0		34,815,000	[4]	0				34,815,000	[4]
Provision for losses		1,296,521,000	1,739,244,000	1,337,574,000	355,984,000	[5]	249,598,000		263,566,000		427,373,000		415,809,000		344,389,000		435,166,000		543,880,000		1,296,521,000		1,739,244,000
Change in reserve for premium deficiency		(7,092,000)	(14,621,000)	(61,504,000)	(665,000)	[6]	(1,942,000)	[6]	(3,102,000)	[6]	(1,383,000)	[6]	(14,664,000)	[6]	8,628,000	[6]	(7,354,000)	[6]	(1,231,000)	[6]	(7,092,000)	[6]	(14,621,000)	[6]
Policy Acquisition Amortization Expense And Other Operating Expenses					51,193,000		56,689,000		60,341,000		60,350,000		59,419,000		54,106,000		51,962,000		79,924,000		228,573,000		245,411,000
Equity in net income of affiliates		65,000	14,668,000	33,226,000	0		0		0		65,000		0	[4]	0	[4]	6,570,000	[4]	8,098,000	[4]	65,000		14,668,000	[4]
Net income (loss)		302,150,000	(1,805,867,000)	(147,879,000)	(121,539,000)	[7]	183,568,000		137,115,000		103,006,000		(1,132,617,000)	[7]	112,185,000		(475,080,000)		(310,355,000)		302,150,000		(1,805,867,000)
Diluted net income (loss) per share		$ 2.26	$ (15.74)	$ (1.80)	$ (0.92)	[8],[9]	$ 1.37	[8],[9]	$ 1.03	[8],[9]	$ 0.77	[8],[9]	$ (8.55)	[8],[9]	$ 0.84	[8],[9]	$ (4.31)	[8],[9]	$ (3.77)	[8],[9]	$ 2.26	[8],[9]	$ (15.74)	[8],[9]
Weighted-average number of common and common equivalent shares outstanding—diluted		133,863	114,697	81,937	133,463	[9]	133,513	[9]	133,614	[9]	133,703	[9]	132,434	[9]	133,520	[9]	110,282	[9]	82,341	[9]	133,863	[9]	114,697	[9]
Valuation Allowance, Deferred Tax Asset, Change in Amount	$ 841,500,000	$ 54,200,000											$ 841,500,000

[1] The 2011 and 2010 periods reflect realized gains and losses on investments in connection with the continued reallocation of our investment portfolio and unrealized gains and losses on our trading securities.

[2] The change in fair value of derivative instruments for 2011 and 2010 reflects the volatility in the cumulative unrealized gain attributable to the market’s perception of our non-performance risk as a result of the changes in our CDS spread during both years.

[3] The 2011 and 2010 periods reflect losses on financial guaranty VIE debt and NIMS VIE debt, offset by realized gains on investments in connection with the continued reallocation of our investment portfolio.

[4] On May 3, 2010, we sold our remaining equity interest in Sherman, which resulted in a gain on sale of affiliate. We no longer record equity in net income of affiliates as a result of the sale.

[5] The provision for losses in the fourth quarter of 2011 was primarily driven by reserves established on new default notices, which increased consistent with seasonal trends. In addition, the results include the effects of an increase in our IBNR reserve estimate.

[6] The 2011 and 2010 periods reflect changes in the provision for second-lien premium deficiency, due to the transfer of premium deficiency reserves to loss reserves, terminations of second-lien transactions, as well as changes in estimates.

[7] The net loss for the fourth quarter of 2011 was primarily due to an increase in both the mortgage insurance and financial guaranty provision for losses. The net loss for the fourth quarter of 2010 was due primarily to the establishment of an $841.5 million valuation allowance against our DTA during the fourth quarter.

[8] Net income (loss) per share is computed independently for each period presented. Consequently, the sum of the quarters may not equal the total net income (loss) per share for the year.(9)The provision for losses in the fourth quarter of 2011 was primarily driven by reserves established on new default notices, which increased consistent with seasonal trends. In addition, the results include the effects of an increase in our IBNR reserve estimate.

[9] Diluted net income (loss) per share and average shares outstanding per the accounting standard regarding earnings per share.