Note 6 - Net Periodic Benefit Costs for Postretirement Medical Plan (Details) - Post Retirement Medical and Life Insurance Plan [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Service cost	$ 27	$ 29	$ 53	$ 57
Interest cost	72	61	144	122
Amortization of prior service credit	(196)	$ (200)	(391)	$ (400)
Amortization of net loss	3		7
	$ (94)	$ (110)	$ (187)	$ (221)