Note 5 - Investments Schedule of Contractual Maturities (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Available-for-sale Securities, Amortized Cost
Available-for-sale Debt Securities, Amortized Cost Basis		$ 2,655,791	$ 1,893,356
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Securities		2,757,508	1,865,461
Debt Securities
Available-for-sale Securities, Amortized Cost
Available-for-sale Debt Securities, Amortized Cost Basis		2,655,791
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Securities		2,757,508
Non Asset Backed Security Investments, Contractual Maturities
Available-for-sale Securities, Amortized Cost
Due in one year or less	[1]	32,821
Due after one year through five years	[1]	267,312
Due after five years through ten years	[1]	701,735
Due after ten years	[1]	387,259
Available-for-sale Securities, Fair Value
Due in one year or less	[1]	32,764
Due after one year through five years	[1]	274,014
Due after five years through ten years	[1]	732,458
Due after ten years	[1]	426,795
RMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	384,867
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	391,701
CMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	446,102
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	462,750
Other ABS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	435,695
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	437,026
2013 Freddie Mac Agreement [Member] | Radian Guaranty Inc [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Restricted		$ 75,800	$ 74,700

[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.