Note 7 - Net Income (Loss) Per Share (Details Textual) - $ / shares shares in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Share-based Payment Arrangement, Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	0.2	0.3
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit (in dollars per share)	$ 10.37	$ 9.83
Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 18.45	$ 19.41
Restricted Stock, Performance-based Stock Units, and Deferred Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	0.3	0.7

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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