Note 6 - Investments Schedule of Contractual Maturities (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Available-for-sale Securities, Amortized Cost
Amortized cost - Debt Securities		$ 2,856,468	$ 1,893,356
Available-for-sale Securities, Fair Value
Fixed-maturities available for sale—at fair value		2,838,512	$ 1,865,461
Debt Securities
Available-for-sale Securities, Amortized Cost
Amortized cost - Debt Securities		2,856,468
Available-for-sale Securities, Fair Value
Fixed-maturities available for sale—at fair value		2,838,512
Non Asset Backed Security Investments, Contractual Maturities
Available-for-sale Securities, Amortized Cost
Due in one year or less	[1]	40,639
Due after one year through five years	[1]	316,744
Due after five years through ten years	[1]	851,375
Due after ten years	[1]	426,788
Available-for-sale Securities, Fair Value
Due in one year or less	[1]	40,570
Due after one year through five years	[1]	317,728
Due after five years through ten years	[1]	841,208
Due after ten years	[1]	425,361
RMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	358,262
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	350,628
CMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	429,057
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	428,289
Other ABS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]	433,603
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]	$ 434,728

[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.