Note 13 - Retirement Benefit Plans - Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Postretirement Health Coverage [Member]
Service cost	$ 0.1	$ 0.1	$ 0.0
Interest cost	0.1	0.2	0.3
Expected return on plan assets	0.0	0.0	0.0
Amortization of net actuarial loss (gain)	0.0	0.0	(0.1)
Net periodic benefit cost (credit)	0.2	0.3	0.2
UNITED STATES | Pension Plan [Member]
Service cost	0.0	0.0	0.0
Interest cost	0.1	0.0	0.1
Expected return on plan assets	0.0	0.0	0.0
Amortization of net actuarial loss (gain)	0.0	0.1	0.0
Net periodic benefit cost (credit)	0.1	0.1	0.1
Foreign Plan [Member] | Pension Plan [Member]
Service cost	0.0	0.0	0.0
Interest cost	0.2	0.2	0.3
Expected return on plan assets	(0.4)	(0.3)	(0.4)
Amortization of net actuarial loss (gain)	0.1	0.0	0.0
Net periodic benefit cost (credit)	$ (0.1)	$ (0.1)	$ (0.1)