Pension and Postretirement Benefit Plans (Obligations and Funded Status) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Pension [Member]
Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	$ 161,892	$ 155,427
Service cost	12,545	11,908	$ 12,173
Interest cost	4,900	5,874	5,582
Participant contributions	0	0
Plan amendments	501	0
Actuarial loss (gain)	3,600	15,085
Benefits paid (including lump sums)	12,520	26,402
Benefit obligation, end of year	170,918	161,892	155,427
Change in Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year	122,583	141,586
Actual return on plan assets	18,527	1,129
Employer contributions	10,635	6,270
Participant contributions	0	0
Benefits paid (including lump sums)	12,520	26,402
Fair value of plan assets, end of year	139,225	122,583	141,586
Under funded status, end of year	(31,693)	(39,309)
Postretirement [Member]
Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	9,666	9,408
Service cost	92	101	117
Interest cost	321	385	407
Participant contributions	787	748
Plan amendments	0	0
Actuarial loss (gain)	(205)	565
Benefits paid (including lump sums)	1,386	1,541
Benefit obligation, end of year	9,275	9,666	9,408
Change in Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	599	793
Participant contributions	787	748
Benefits paid (including lump sums)	1,386	1,541
Fair value of plan assets, end of year	0	0	$ 0
Under funded status, end of year	$ (9,275)	$ (9,666)