Commitments and Contingencies - Contractual Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016
Capital Lease Obligations
2017	$ 988
2018	881
2019	126
2020	51
2021	4
Thereafter	0
Total minimum lease payments	2,050
Less: imputed interest (0.82% to 10.7%)	(90)
Present value of future minimum lease payments	1,960
Less: current portion	1,261	$ 1,323
Other long-term liabilities-capital leases	699	$ 1,036
Operating Lease Obligations
2017	3,052
2018	3,620
2019	2,817
2020	1,360
2021	441
Thereafter	61
Future Minimum Payments Due	11,351
Purchase Commitments
2017	78,385
2018	496
2019	0
2020	0
2021	0
Thereafter	0
Future minimum purchase commitments	78,881
Pension Plan [Member]
Defined Benefit Plan Obligations
2017	6,056
2018	8,304
2019	8,554
2020	8,844
2021	9,074
Thereafter	47,099
Future payments due	87,931
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Obligations
2017	810
2018	1,102
2019	1,143
2020	1,176
2021	1,210
Thereafter	6,246
Future payments due	11,687
Minimum
Capital Lease Obligations
Imputed interest rate on capital leases		0.82%
Maximum
Capital Lease Obligations
Imputed interest rate on capital leases		10.70%
Revolving Credit Facility
Revolving Credit Facility
2017	200
2018	0
2019	0
2020	0
2021	0
Thereafter	0
Future minimum debt maturities	200
Texas Facility Construction Contract [Member]
Purchase Commitments
2017	14,435
2018	0
2019	0
2020	0
2021	0
Thereafter	0
Future minimum purchase commitments	$ 14,435