Note 8 - Pension and Post-retirement Benefits - Net Periodic Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Pension Plan [Member]
Service cost
Interest cost	1,500	1,518	3,006	3,029
Expected return on plan assets	(1,279)	(1,291)	(2,563)	(2,576)
Amortization of net loss	7	6	14	12
	228	233	457	465
Post Retirement Medical Plan [Member]
Service cost	18	22	36	43
Interest cost	67	67	133	134
Amortization of net loss	8	25	15	50
	(42)	(21)	(85)	(42)
Amortization of prior service credit	$ (135)	$ (135)	$ (269)	$ (269)