Note 6 - Investments Schedule of Contractual Maturities (Details) - USD ($) $ in Thousands		1 Months Ended	4 Months Ended	48 Months Ended
		Oct. 31, 2015	Dec. 31, 2015	Dec. 31, 2015	Aug. 29, 2017	Dec. 31, 2014
Available-for-sale Securities, Amortized Cost
Amortized cost			$ 1,893,356	$ 1,893,356		$ 528,660
Available-for-sale Securities, Fair Value
Fixed-maturities available for sale—at fair value			1,865,461	1,865,461		$ 536,890
Debt Securities
Available-for-sale Securities, Amortized Cost
Amortized cost			1,893,356	1,893,356
Available-for-sale Securities, Fair Value
Fixed-maturities available for sale—at fair value			1,865,461	1,865,461
Non Asset Backed Security Investments, Contractual Maturities
Available-for-sale Securities, Amortized Cost
Due in one year or less	[1]		0	0
Due after one year through five years	[1]		173,191	173,191
Due after five years through ten years	[1]		437,248	437,248
Due after ten years	[1]		280,941	280,941
Available-for-sale Securities, Fair Value
Due in one year or less	[1]		0	0
Due after one year through five years	[1]		172,705	172,705
Due after five years through ten years	[1]		430,476	430,476
Due after ten years	[1]		274,971	274,971
RMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]		226,744	226,744
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]		224,905	224,905
CMBS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]		415,780	415,780
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]		406,910	406,910
Other ABS
Available-for-sale Securities, Amortized Cost
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[2]		359,452	359,452
Available-for-sale Securities, Fair Value
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[2]		355,494	355,494
2013 Freddie Mac Agreement [Member] | Mortgage Insurance Segment
Total Debt Securities [Line Items]
Final Loss Mitigation Activity		$ 135,900	$ 4,400
Not Final Loss Mitigation Activity				$ 8,900
Maximum [Member] | 2013 Freddie Mac Agreement [Member] | Scenario, Forecast [Member] | Mortgage Insurance Segment
Total Debt Securities [Line Items]
Restricted Investments Held as Collateral for Master Transaction Agreement, Net					$ 74,000

[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.