Note 13 - Employee Retirement Plans (Details Textual) - USD ($) $ in Thousands		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Credit Risk of Plan Assets, Long Duration Corporate Bonds		56.00%
Currency Fluctuations Assets Invested In Non Us Investments		6.00%
Liquidity Risk Long-term Investments In Private Equity and Real Estate		1.00%
Defined Contribution Plan, Cost		$ 98,000	$ 76,000	$ 108,000
Equity Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		40.00%
Bond Investments [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		60.00%
Minimum [Member]
Percent To Yield		10.00%
Maximum [Member]
Percent To Yield		40.00%
Pension Plan [Member]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ (358,000)	$ 124,000
Defined Benefit Plan, Accumulated Benefit Obligation	$ 4,700,000	4,500,000	4,700,000
Pension Plan [Member] | UNITED STATES
Defined Benefit Plan Voluntary Contributions by Employer		0	180,000
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 16,000	195,000
Weighted Average Discount Rate, Rounded Amount	0.78%	0.37%
Pension Plan [Member] | Foreign Plan [Member]
Defined Benefit Plan Voluntary Contributions by Employer		$ 24,000	41,000
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		29,000
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 31,000	50,000
Weighted Average Discount Rate, Rounded Amount		0.18%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 9,000	60,000
Cap On Contribution Toward Future Retiree Medical Coverage		120.00%
Percentage Of Cost To Be Paid By Employees For Retiree Medical Upon Retirement		100.00%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		$ 105,000	$ (58,000)
Weighted Average Discount Rate, Rounded Amount		0.30%	0.72%
Other Postretirement Benefits Plan [Member] | UNITED STATES
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 0	$ 30,000