Note 8 - Pension and Post-retirement Benefits - Net Periodic Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Pension Plan [Member]
Service cost
Interest cost	1,506	1,511
Expected return on plan assets	(1,284)	(1,285)
Amortization of net loss	7	6
	229	232
Other Postretirement Benefits Plan [Member]
Service cost	18	21
Interest cost	66	67
Amortization of net loss	7	25
	(43)	(21)
Amortization of prior service credit	$ (134)	$ (134)