Note 9 - Pensions and Other Postretirement Benefits - Allocation of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Plan Fair Value Assets	$ 72,658	$ 77,067
Fair Value, Inputs, Level 1 [Member]
Plan Fair Value Assets	25,032	26,398
Fair Value, Inputs, Level 2 [Member]
Plan Fair Value Assets	47,487	50,649
Fair Value, Inputs, Level 3 [Member]
Plan Fair Value Assets	139	20
Equity Securities [Member]
Plan Fair Value Assets	10,979	12,639
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Plan Fair Value Assets	10,979	12,619
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Plan Fair Value Assets	0	0
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Plan Fair Value Assets	0	20
Fixed Income Securities [Member]
Plan Fair Value Assets	51,081	55,045
Fixed Income Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Plan Fair Value Assets	8,788	9,582
Fixed Income Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Plan Fair Value Assets	42,154	45,463
Fixed Income Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Plan Fair Value Assets	139	0
Mutual Funds [Member]
Plan Fair Value Assets	3,045	2,108
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Plan Fair Value Assets	3,045	2,108
Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Plan Fair Value Assets		0
Mutual Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Plan Fair Value Assets	0	0
Cash and Cash Equivalents [Member]
Plan Fair Value Assets	7,553	7,275
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Plan Fair Value Assets	2,220	2,089
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Plan Fair Value Assets	5,333	5,186
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Plan Fair Value Assets	$ 0	$ 0