Note 12 - Employee Benefit and Retirement Plans - Portfolio by Valuation Category (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019
Asset Allocation	100.00%	100.00%
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 54,112	$ 45,809
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	64,315	76,224
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 118,427	$ 122,033
Cash Equivalents [Member]
Asset Allocation	4.00%	2.00%
Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 5,165	$ 1,818
Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Cash Equivalents [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 5,165	$ 1,818
Fixed Income Securities [Member]
Asset Allocation	27.00%	31.00%
Fixed Income Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Fixed Income Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	32,740	38,232
Fixed Income Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Fixed Income Securities [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 32,740	$ 38,232
Equity Securities [Member]
Asset Allocation	40.00%	35.00%
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 48,947	$ 41,629
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	888	1,482
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Equity Securities [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 49,835	$ 43,111
Mutual and Pooled Funds [Member]
Asset Allocation	29.00%	32.00%
Mutual and Pooled Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		$ 2,362
Mutual and Pooled Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	30,687	36,510
Mutual and Pooled Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Mutual and Pooled Funds [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 30,687	$ 38,872