Note 12 - Employee Benefit and Retirement Plans (Details Textual) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2016
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment		$ (6,900,000)
Defined Contribution Plan, Employer Discretionary Contribution Amount		$ 1,300,000	$ 800,000	$ 800,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		4.31%			3.77%
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		$ 4,170,000
Pension Cost (Reversal of Cost)		3,900,000	22,200,000	$ 4,600,000
Fair Value of the Company's Common Stock		6,900,000	$ 9,700,000
Post Retirement Medical and Life Insurance Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		$ 370,000
UNITED STATES
Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return on Assets		5.00%	5.50%	6.00%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.92%	3.77%	4.49%
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		$ 4,170,000
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		3,300,000
UNITED STATES | Pension Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		$ 3,300,000
UNITED STATES | Post Retirement Medical and Life Insurance Plan [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.92%	3.77%	4.49%
UNITED KINGDOM
Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return on Assets		3.59%	4.77%	5.45%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		2.73%	3.00%	3.90%
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year			$ 1,000,000
UNITED KINGDOM | Pension Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		$ 1,000,000
Scenario, Forecast [Member] | UNITED STATES
Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return on Assets	5.00%
Scenario, Forecast [Member] | UNITED KINGDOM
Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return on Assets	3.00%
Maximum [Member]
Fixed Contribution Toward Medical Premium for Retirees 65 and Older			28.50
Maximum [Member] | Equity Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		70.00%
Maximum [Member] | Company Stock [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		20.00%
Maximum [Member] | Cash and Debt Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		60.00%
Minimum [Member]
Fixed Contribution Toward Medical Premium for Retirees 65 and Older			$ 23
Minimum [Member] | Equity Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		40.00%
Minimum [Member] | Company Stock [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		10.00%
Minimum [Member] | Cash and Debt Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		30.00%