Note 18 - Discontinued Operations Disposal Group, Income Statement, Balance Sheet and Additional Disclosures (Details) - USD ($)		3 Months Ended								12 Months Ended
	Apr. 01, 2015	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net investment income		$ 33,605,000	$ 32,540,000	$ 30,071,000	$ 31,032,000	$ 28,996,000	$ 28,430,000	$ 28,839,000	$ 27,201,000	$ 127,248,000	$ 113,466,000	$ 81,537,000
Other Income										2,886,000	3,572,000	2,899,000
Total revenues										1,221,631,000	1,238,452,000	1,193,253,000
Policy acquisition costs		5,871,000	5,554,000	6,123,000	6,729,000	5,579,000	6,119,000	5,393,000	6,389,000	24,277,000	23,480,000	22,424,000
Other operating expenses		$ 65,999,000	$ 64,195,000	$ 68,750,000	$ 68,377,000	$ 62,416,000	$ 62,119,000	$ 63,173,000	$ 57,188,000	267,321,000	244,896,000	242,405,000
Total expenses										874,894,000	754,766,000	755,424,000
Income (loss) from discontinued operations, net of tax										$ 0	$ 0	5,385,000
Discontinued Operations, Held-for-sale [Member] | Radian Asset Assurance [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Provision for Loss (Gain) on Disposal, before Income Tax												(14,300,000)
Total Operating Expenses and Interest Expense Allocated to Subsidiaries From Parent Company												0
Total revenues												34,300,000
Income (loss) from discontinued operations, net of tax												$ 5,400,000
Discontinued Operations, Disposed of by Sale [Member] | Radian Asset Assurance [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of Stock, Percentage of Ownership before Transaction	100.00%
Disposal Group, Including Discontinued Operation, Consideration	$ 810,000,000
Equity Method Investment, Net Sales Proceeds	$ 789,000,000