Condensed Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 27,621	$ 14,471	$ 102,927	$ 86,827
Defined Benefit Pension and Postretirement Benefit Plans:
Amortization of loss, before tax	134	170	402	508
Amortization of prior service credit, before tax	(45)	(46)	(136)	(136)
Total Other Comprehensive Income, Before Tax	89	124	266	372
Tax Attributes of Items in Other Comprehensive Income:
Amortization of loss, tax	(41)	(63)	(140)	(188)
Amortization of prior service credit, tax	14	17	47	50
Total Tax Expense	(27)	(46)	(93)	(138)
Other Comprehensive Income, Net of Tax	62	78	173	234
Comprehensive Income	$ 27,683	$ 14,549	$ 103,100	$ 87,061