Note 10 - Losses and LAE Mortgage Insurance Loss Reserves Rollforward (Details) $ in Thousands	6 Months Ended				12 Months Ended
	Jun. 30, 2018 USD ($) incident		Jun. 30, 2017 USD ($)		Dec. 31, 2017 USD ($)
Liability for Claims and Claims Adjustment Expense [Line Items]
Number of Natural Disasters | incident	2
Loss reserve [Roll Forward]
Balance at January 1	$ 507,588
Deduct paid claims and LAE related to [Abstract]
Balance at September 30	$ 451,542				$ 507,588
Mortgage Insurance Segment
Liability for Claims and Claims Adjustment Expense [Line Items]
Average Default To Claim Rate Estimate, Gross, For New Defaults	9.00%
Loss reserve [Roll Forward]
Balance at January 1	$ 507,588		$ 760,269		760,269
Less reinsurance recoverables	8,350	[1]	6,851	[1]	6,851	[1]
Balance at beginning of period, net of reinsurance recoverables	499,238		753,418		753,418
Add losses and LAE incurred in respect of default notices reported and unreported in [Abstract]
Current year	67,286	[2]	88,906	[2]
Prior years	(11,311)		(24,721)
Total incurred losses and LAE	55,975		64,185
Deduct paid claims and LAE related to [Abstract]
Paid Losses and LAE Current year	1,091	[2]	1,027	[2]
Paid losses and LAE Prior years	115,369		172,356
Total paid losses and LAE	116,460		173,383
Balance at end of period, net of reinsurance recoverables	438,753		644,220		499,238
Add reinsurance recoverables	9,341	[1]	7,371	[1]	8,350	[1]
Balance at September 30	448,094		$ 651,591		507,588
Default To Claim Rate Detail [Abstract]
Default To Claim Rate Estimate, Gross, For New Defaults			11.00%
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	6,200				10,400
Mortgage Insurance Segment | Pool Insurance Mortgage Insurance Product [Member]
Loss reserve [Roll Forward]
Balance at January 1	13,463	[3]
Less reinsurance recoverables	35	[4]
Deduct paid claims and LAE related to [Abstract]
Add reinsurance recoverables	24	[4]			35	[4]
Balance at September 30	12,197	[3]			13,463	[3]
Mortgage Insurance Segment | Primary Mortgage Product [Member]
Loss reserve [Roll Forward]
Less reinsurance recoverables	8,315	[4]
Deduct paid claims and LAE related to [Abstract]
Add reinsurance recoverables	$ 9,317	[4]			$ 8,315	[4]
Default To Claim Rate Detail [Abstract]
Weighted Average Default To Claim Rate Assumption Net Of Denials Rescissions and Reinstatements	35.00%				31.00%
Weighted Average Default To Claim Rate Assumption Net Of Denials Rescissions and Reinstatements Excluding Defaults in FEMA Designated Areas	38.00%				38.00%
Default To Claim Rate Estimate, Gross, For Pre-Foreclosure Stage Defaults	68.00%
Gross Default To Claim Rate Estimate	75.00%
Hurricanes Harvey and Irma [Member] | Mortgage Insurance Segment | Primary Mortgage Product [Member]
Default To Claim Rate Detail [Abstract]
Default To Claim Rate Estimate, Gross, For New Defaults	3.00%

[1] Related to ceded losses recoverable, if any, on captive reinsurance transactions, the QSR Program and the Single Premium QSR Program. See Note 7 for additional information.

[2] Related to underlying defaulted loans with a most recent default notice dated in the year indicated. For example, if a loan had defaulted in a prior year, but then subsequently cured and later re-defaulted in the current year, that default would be considered a current year default.

[3] Includes reinsurance recoverable of $24 thousand and $35 thousand as of June 30, 2018 and December 31, 2017, respectively.

[4] Represents ceded losses on captive reinsurance transactions, the QSR Program and the Single Premium QSR Program.