Note 13 - Retirement Benefit Plans - Weighted-average Asset Allocations by Asset Category (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Asset		$ 0
Pension Plan [Member]
Asset			$ 13,300
Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Asset			0
Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Asset			0
Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Asset			13,300
Pension Plan [Member] | Foreign Plan [Member]
Asset		12,900	13,300	$ 12,200
Pension Plan [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Asset		0
Pension Plan [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Asset		0
Pension Plan [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Asset		12,900
Pension Plan [Member] | Investment Account Held by Pension Plan [Member]
Asset	[1]		13,300
Pension Plan [Member] | Investment Account Held by Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Asset	[1]		0
Pension Plan [Member] | Investment Account Held by Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Asset	[1]		0
Pension Plan [Member] | Investment Account Held by Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Asset	[1]		$ 13,300
Pension Plan [Member] | Investment Account Held by Pension Plan [Member] | Foreign Plan [Member]
Asset	[1]	12,900
Pension Plan [Member] | Investment Account Held by Pension Plan [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Asset	[1]	0
Pension Plan [Member] | Investment Account Held by Pension Plan [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Asset	[1]	0
Pension Plan [Member] | Investment Account Held by Pension Plan [Member] | Foreign Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Asset	[1]	$ 12,900

[1] This category is comprised of investments in insurance contracts.