Note 9 - Employee Benefit Plans - Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current liabilities:
Accrued benefit liability	$ (758)	$ (622)
Accrued benefit liability	(44,144)	(56,219)
Accumulated other comprehensive loss	53,085	49,525
Net amount recognized	$ 8,183	$ (7,316)

Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant