FINANCING ARRANGEMENTS: Additional Information (Details) - USD ($)	Mar. 31, 2017	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt	$ 120,351,000	$ 119,606,000
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, net
Debt Instrument [Line Items]
Debt face amount			$ 123,000,000.0
Interest rate percentage	5.50%		5.50%
Unamortized discount	$ 2,002,000	2,565,000	$ 3,000,000
Long-term debt	120,351,000	119,606,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt	0	0
Maximum borrowing capacity	200,000,000
Outstanding standby letters of credit	1,500,000	1,600,000
Revolving credit facility remaining borrowing capacity	$ 198,500,000	$ 198,400,000