Note 3 - Segment Reporting Schedule of Segment Reporting Information by Segment (Details)		3 Months Ended
		Mar. 31, 2019 USD ($) segment		Mar. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment		2
Net premiums written—insurance		$ 253,320,000		$ 237,980,000
Net premiums earned—insurance		263,512,000		242,550,000
Services revenue		32,753,000		33,164,000
Net investment income		43,847,000		33,956,000
Other income		1,604,000		807,000
Policy acquisition costs		5,893,000		7,117,000
Cost of services		24,157,000		23,126,000
Other operating expenses before corporate allocations		78,805,000		63,243,000
Restructuring and other exit costs		0		551,000
Adjusted pretax operating income (loss)		202,070,000		164,103,000
Net gains (losses) on investments and other financial instruments		21,913,000		(18,887,000)
Mortgage Insurance Segment
Segment Reporting Information [Line Items]
Net premiums written—insurance	[1]	251,586,000		237,980,000
(Increase) decrease in unearned premiums		10,192,000		4,570,000
Net premiums earned—insurance		261,778,000		242,550,000
Net investment income		43,665,000		33,956,000
Other income		1,196,000		807,000
Total	[2]	306,639,000		277,313,000
Provision for losses		20,844,000		37,391,000
Policy acquisition costs		5,893,000		7,117,000
Other operating expenses before corporate allocations		30,410,000		31,888,000
Total	[3]	57,147,000		76,396,000
Adjusted pretax operating income (loss) before corporate allocations		249,492,000		200,917,000
Allocation of corporate operating expenses		25,625,000		18,577,000
Allocation of interest expense		15,697,000		10,629,000
Adjusted pretax operating income (loss)	[4]	208,170,000		171,711,000
Inter-segment expenses		970,000		1,002,000
Mortgage and Real Estate Services Segment
Segment Reporting Information [Line Items]
Corporate Cash and Investments Allocated to Segments		0
Net premiums earned—insurance	[5]	1,734,000		0
Services revenue	[6]	33,723,000		34,166,000
Net investment income	[5]	182,000		0
Other income	[5]	408,000		0
Total	[6]	36,047,000		34,166,000
Provision for losses	[5]	(18,000)		0
Cost of services		24,559,000		23,270,000
Other operating expenses before corporate allocations		13,435,000		10,744,000
Restructuring and other exit costs		0		525,000
Total		37,976,000		34,539,000
Adjusted pretax operating income (loss) before corporate allocations		(1,929,000)		(373,000)
Allocation of corporate operating expenses		4,171,000		2,784,000
Allocation of interest expense		0	[7]	4,451,000
Adjusted pretax operating income (loss)	[4]	(6,100,000)		(7,608,000)
Inter-segment revenues		$ 970,000		$ 1,002,000

[1] Net of ceded premiums written under our reinsurance programs. See Note 7 for additional information.

[2] Excludes net gains on investments and other financial instruments of $21.9 million for the three months ended March 31, 2019, and net losses on investments and other financial instruments of $18.9 million for the three months ended March 31, 2018, not included in adjusted pretax operating income.

[3] Includes inter-segment expenses as follows:   Three Months Ended
March 31, (In thousands) 2019   2018 Inter-segment expenses $ 970
  $ 1,002

[4] Includes inter-segment expenses and revenues as listed in the notes to the preceding tables.

[5] Results from inclusion of the operations of EnTitle Direct, a national title insurance and settlement services company, acquired in March 2018.

[6] Includes inter-segment revenues as follows:   Three Months Ended
March 31, (In thousands) 2019   2018 Inter-segment revenues $ 970
  $ 1,002

[7] Effective January 1, 2019, the Clayton Intercompany Note was repaid using proceeds from an additional capital contribution from Radian Group. As a result of the intercompany note repayment, the Services segment no longer incurs interest expense on the intercompany note.