Note 16 - Subsequent Events 2018 Single Premium QSR Transaction (Details) - 2018 Single Premium QSR [Member] - Scenario, Forecast [Member] $ in Millions	1 Months Ended
Oct. 31, 2017 USD ($) reinsurer
Subsequent Event [Line Items]
Third-Party Reinsurers \| reinsurer	8
Percentage of NIW Able to be Ceded Under QSA	65.00%
Ceded Premiums Written \| $	$ 335
Ceded Insurance Commission Percentage	25.00%
Maximum [Member]
Subsequent Event [Line Items]
Loss Ratio	56.00%

Amount of written premiums ceded to other entities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

Name:	us-gaap_CededPremiumsWritten
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration