Note 6 - Share-based Payments - Stock Incentive Awards Granted to Officers Under the 2014 Stock Incentive Plan (Details)	Feb. 13, 2019 $ / shares shares
Restricted Stock Units (RSUs) [Member] \| The 2014 Stock Incentive Plan [Member]
Shares/units granted (in shares) \| shares	15,600
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) \| $ / shares	$ 49.6225
Shares/units granted, vesting date	Feb. 06, 2023
Performance Shares [Member] \| The 2014 Stock Incentive Plan [Member]
Shares/units granted (in shares) \| shares	47,800
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) \| $ / shares	$ 42.875
Shares/units granted, vesting date	Dec. 31, 2021
Performance Shares [Member] \| The 2014 Stock Incentive Plan Under Legacy Agreement [Member]
Shares/units granted (in shares) \| shares	7,800
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) \| $ / shares	$ 45.885
Shares/units granted, vesting date	Dec. 31, 2021

Represents the award vesting date under a share-based compensation arrangement.

No definition available.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ 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 (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

+ Details

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