Note 9 - Pensions and Other Postretirement Benefits - Amounts Recognized in the Company's Consolidated Balance Sheets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in plan assets:
Plan assets at beginning of year	$ 77,067,000
Plan assets at end of year	72,658,000	$ 77,067,000
Pension Plan [Member]
Benefit obligation at beginning of year	86,299,000	81,325,000
Service cost	2,662,000	2,709,000	$ 2,204,000
Interest cost	1,729,000	1,937,000	2,454,000
Settlement	651,000	1,854,000
Benefits paid	(7,719,000)	(12,872,000)
Effect of foreign exchange
Actual expenses	(150,000)	(150,000)
Actuarial (gain)/ loss	(1,472,000)	11,496,000
Benefit obligation at end of year	82,000,000	86,299,000	81,325,000
Change in plan assets:
Plan assets at beginning of year	77,067,000	80,285,000
Actual return on plan assets	1,460,000	7,804,000
Employer contributions	2,000,000	2,000,000
Benefits paid	(7,719,000)	(12,872,000)
Actual expenses	(150,000)	(150,000)
Plan assets at end of year	72,658,000	77,067,000	80,285,000
Funded status at end of year	(9,342,000)	(9,232,000)
Current liabilities	0	0
Noncurrent liabilities	(9,342,000)	(9,232,000)
Total assets (liabilities)	(9,342,000)	(9,232,000)
Net actuarial loss	26,016,000	28,896,000
Prior Service Cost	0	0
Deferred tax (benefit) expense	(6,446,000)	(7,130,000)
After tax actuarial loss (gain)	19,570,000	21,766,000
Postemployment Retirement Benefits [Member]
Benefit obligation at beginning of year	29,848,000	26,055,000
Service cost	1,462,000	1,372,000	1,083,000
Interest cost	654,000	778,000	941,000
Settlement	0	0
Benefits paid	(1,618,000)	(1,305,000)
Effect of foreign exchange	1,000	9,000
Actual expenses	0	0
Actuarial (gain)/ loss	(1,413,000)	2,939,000
Benefit obligation at end of year	28,934,000	29,848,000	26,055,000
Change in plan assets:
Plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	1,618,000	1,305,000
Benefits paid	(1,618,000)	(1,305,000)
Actual expenses	0	0
Plan assets at end of year	0	0	$ 0
Funded status at end of year	(28,934,000)	(29,848,000)
Current liabilities	(1,575,000)	(1,598,000)
Noncurrent liabilities	(27,359,000)	(28,250,000)
Total assets (liabilities)	(28,934,000)	(29,848,000)
Net actuarial loss	5,841,000	7,834,000
Prior Service Cost	(2,125,000)	(3,255,000)
Deferred tax (benefit) expense	(807,000)	(1,012,000)
After tax actuarial loss (gain)	$ 2,909,000	$ 3,567,000