Note 8 - Pension - Changes in Projected Benefit Obligations and Fair Value of Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Projected benefit obligation	$ 352,572	$ 386,020
Service cost	4,400	5,151
Interest cost	16,598	15,599
Exchange rate fluctuations	1,549	138
Actuarial (gain) loss	37,698	(31,537)
Settlements paid	(112)
Benefits paid	(22,955)	(22,799)
Projected benefit obligation	389,750	352,572
Fair value of plan assets	304,084	343,219
Actual return on plan assets	61,961	(19,533)
Contributions made in 2019	3,322	3,197
Settlements paid	(112)
Benefits paid	(22,955)	(22,799)
Fair value of plan assets	$ 346,300	$ 304,084
Funded ratio	88.90%	86.20%
Funded status and net accrued pension benefit cost	$ (43,450)	$ (48,488)
UNITED STATES
Projected benefit obligation	322,594	354,053
Service cost	3,368	4,009
Interest cost	13,530	12,615
Exchange rate fluctuations
Actuarial (gain) loss	28,820	(28,481)
Settlements paid	(112)
Benefits paid	(19,745)	(19,602)
Projected benefit obligation	348,455	322,594
Fair value of plan assets	304,084	343,219
Actual return on plan assets	61,961	(19,533)
Contributions made in 2019	112
Settlements paid	(112)
Benefits paid	(19,745)	(19,602)
Fair value of plan assets	$ 346,300	$ 304,084
Funded ratio	99.40%	94.30%
Funded status and net accrued pension benefit cost	$ (2,155)	$ (18,510)
Foreign Plan [Member]
Projected benefit obligation	29,978	31,967
Service cost	1,032	1,142
Interest cost	3,068	2,984
Exchange rate fluctuations	1,549	138
Actuarial (gain) loss	8,878	(3,056)
Settlements paid
Benefits paid	(3,210)	(3,197)
Projected benefit obligation	41,295	29,978
Fair value of plan assets
Actual return on plan assets
Contributions made in 2019	3,210	3,197
Settlements paid
Benefits paid	(3,210)	(3,197)
Fair value of plan assets
Funded ratio	0.00%	0.00%
Funded status and net accrued pension benefit cost	$ (41,295)	$ (29,978)

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Amount of foreign currency translation gain (loss) which (increases) decreases benefit obligation of defined benefit plan.

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Percentage of plan assets to benefit obligation of defined benefit plan.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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Amount of cost recognized for passage of time related to defined benefit plan.

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Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of (increase) decrease to benefit obligation of defined benefit plan from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Includes, but is not limited to, lump-sum cash payment to participant in exchange for right to receive specified benefits, purchase of nonparticipating annuity contract and change from remeasurement.

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Amount of payment, which decreases plan assets of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract.

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