FINANCING ARRANGEMENTS: Additional Information (Details) - USD ($)	6 Months Ended
	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt	$ 121,096,000	$ 120,599,000
Senior Notes | Senior Term Notes 5.75%
Debt Instrument [Line Items]
Debt face amount			$ 120,000,000
Interest rate percentage			5.75%
Senior Notes | Senior Term Notes
Debt Instrument [Line Items]
Debt face amount			$ 123,000,000.0
Interest rate percentage	5.50%		5.50%
Unamortized discount	$ 1,439,000	1,815,000	$ 3,000,000
Long-term debt	121,096,000	120,599,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 200,000,000
Debt term	5 years
Long-term debt	$ 0	0
Outstanding standby letters of credit	1,500,000	1,500,000
Revolving credit facility remaining borrowing capacity	$ 198,500,000	$ 198,500,000