Note 5 - Investments Unrealized Gain (Loss) on Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2016		Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	$ 2,655,791		$ 1,893,356
Available-for-sale Securities	2,758,838		1,940,891
Available-for-sale Equity Securities, Amortized Cost Basis	1,330		75,538
Available-for-sale Securities, Equity Securities	1,330		75,430
Amortized Cost Debt and Equity Securities	2,657,121		1,968,894
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	103,849		6,297
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	2,132		34,300
US government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	42,213		13,773
Available-for-sale Securities	45,035		13,752
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	2,846		0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	24		21
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	68,520		36,920
Available-for-sale Securities	75,320		37,900
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	6,800		1,100
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0		120
Corporate bonds and notes
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,249,233		815,024
Available-for-sale Securities	1,315,525		802,193
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	66,683		4,460
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	391		17,291
RMBS
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	384,867		226,744
Available-for-sale Securities	391,701		224,905
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	7,054		625
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	220		2,464
CMBS
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	446,102		415,780
Available-for-sale Securities	462,750		406,910
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	17,090		69
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	442		8,939
Other ABS
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	435,695		359,452
Available-for-sale Securities	437,026		355,494
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	2,335		16
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	1,004		3,974
Foreign government securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	27,161		25,663
Available-for-sale Securities	28,151		24,307
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,041		27
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	51		1,383
Other than Securities Investment [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	2,000
Available-for-sale Securities	2,000
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	2,655,791		1,893,356
Available-for-sale Securities	2,757,508		1,865,461
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	103,849		6,297
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	2,132		34,192
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	1,330	[1]	75,538	[2]
Available-for-sale Securities, Equity Securities	1,330	[1]	75,430	[2]
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax	0	[1]	0	[2]
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax	$ 0	[1]	$ 108	[2]

[1] Comprised primarily of investments in Federal Home Loan Bank stock required in connection with the memberships of Radian Guaranty and Radian Reinsurance in the Federal Home Loan Bank of Pittsburgh.

[2] Comprised primarily of a multi-sector exchange-traded fund.