Note 5 - Investments Schedule of Contractual Maturities (Details) - USD ($) $ in Thousands		1 Months Ended		45 Months Ended
		Oct. 31, 2015	Sep. 30, 2015	Sep. 30, 2015	Aug. 29, 2017	Dec. 31, 2014
Available-for-sale Securities, Amortized Cost
Available-for-sale Debt Securities, Amortized Cost Basis			$ 1,507,522	$ 1,507,522		$ 528,660
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Securities			1,496,328	1,496,328		536,890
Debt Securities
Available-for-sale Securities, Amortized Cost
Available-for-sale Debt Securities, Amortized Cost Basis			1,507,522	1,507,522
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Securities			1,496,328	1,496,328
Non Asset Backed Security Investments, Contractual Maturities
Available-for-sale Securities, Amortized Cost
Due in one year or less	[1]		2,292	2,292
Due after one year through five years	[1]		104,053	104,053
Due after five years through ten years	[1]		368,126	368,126
Due after ten years	[1]		186,838	186,838
Available-for-sale Securities, Fair Value
Due in one year or less	[1]		2,299	2,299
Due after one year through five years	[1]		104,854	104,854
Due after five years through ten years	[1]		363,447	363,447
Due after ten years	[1]		182,254	182,254
RMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]		208,011	208,011
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]		209,028	209,028
CMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]		307,216	307,216
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]		305,700	305,700
Other ABS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]		330,986	330,986
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]		328,746	328,746
2013 Freddie Mac Agreement [Member] | Mortgage Insurance Segment
Available-for-sale Securities, Fair Value
Final Loss Mitigation Activity			1,000
Not Final Loss Mitigation Activity				11,000
2013 Freddie Mac Agreement [Member] | Mortgage Insurance Segment | Maximum [Member] | Scenario, Forecast [Member]
Available-for-sale Securities, Fair Value
Restricted Investments Held as Collateral for Master Transaction Agreement, Net					$ 74,000
2013 Freddie Mac Agreement [Member] | Radian Guaranty Inc [Member]
Available-for-sale Securities, Fair Value
Restricted Investments Held as Collateral for Master Transaction Agreement, Net			$ 210,900	$ 210,900		$ 209,300
Subsequent Event [Member] | 2013 Freddie Mac Agreement [Member] | Mortgage Insurance Segment
Available-for-sale Securities, Fair Value
Final Loss Mitigation Activity		$ 135,900

[1] Actual maturities may differ as a result of calls before scheduled maturity.

[2] RMBS, CMBS and Other ABS are shown separately, as they are not due at a single maturity date.