Note 13 - Commitments and Contingencies Legal Proceedings (Details)	12 Months Ended
	Dec. 31, 2017 matter	Jun. 05, 2017 Certificates	Dec. 17, 2016 Certificates
Loss Contingencies [Line Items]
Minimum Number of Pending or Threatened Matters That Could Effect Our Results | matter	1
Insurance Claims [Member] | Total Primary Insurance Mortgage Insurance Products [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Loss Contingency, Legal Actions Commencement, Period	2 years
Insurance Claims [Member] | Pool Insurance Mortgage Insurance Product [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Loss Contingency, Legal Actions Commencement, Period	3 years
Initial [Member]
Loss Contingencies [Line Items]
Insurance Certificates Issued Under Multiple Insurance Policies			9,420
Amended [Member]
Loss Contingencies [Line Items]
Insurance Certificates Issued Under Multiple Insurance Policies		8,870