Note 12 - Retirement Benefits (Details Textual) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($)
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage	100.00%
Defined Contribution Plan, Employers Matching Contribution, Requisite Service Period (Year)	5 years
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0

Percentage of employer's matching contributions to a defined contribution plan that vests in a given year.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration