Note 7 - Pension and Post-retirement Benefits - Net Periodic Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Service cost		$ 614		$ 1,405
Interest cost	1,518	1,533	3,029	3,085
Expected return on plan assets	(1,291)	(1,288)	(2,576)	(2,594)
Amortization of net loss	6	68	12	96
	233	927	465	1,992
Other Postretirement Benefits Plan [Member]
Service cost	22	24	43	47
Interest cost	67	68	134	136
Amortization of net loss	25	30	50	60
	(21)	(47)	(42)	(94)
Amortization of prior service credit	$ (135)	$ (169)	$ (269)	$ (337)