Note 5 - Investments Schedule of Contractual Maturities (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Available-for-sale Securities, Amortized Cost
Available-for-sale Debt Securities, Amortized Cost Basis		$ 3,129,901	$ 2,856,468
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Securities		3,158,843	2,838,512
Debt Securities
Available-for-sale Securities, Amortized Cost
Available-for-sale Debt Securities, Amortized Cost Basis		3,129,901
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Securities		3,158,843
Non Asset Backed Security Investments, Contractual Maturities
Available-for-sale Securities, Amortized Cost
Due in one year or less	[1]	59,342
Due after one year through five years	[1]	656,233
Due after five years through ten years	[1]	874,709
Due after ten years	[1]	326,474
Available-for-sale Securities, Fair Value
Due in one year or less	[1]	59,351
Due after one year through five years	[1]	661,676
Due after five years through ten years	[1]	880,162
Due after ten years	[1]	341,973
RMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	184,603
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	182,716
CMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	432,124
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	435,101
Other ABS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	596,416
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	597,864
2013 Freddie Mac Agreement [Member] | Radian Guaranty Inc [Member]
Available-for-sale Securities, Fair Value
Marketable Securities, Restricted		$ 64,300	$ 63,900

[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.