Income Taxes - Components of Net Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2018
Deferred Tax Assets
Net Operating Loss Carryforwards	$ 28,886	$ 39,884
Inventory Valuation and Reserves	8,230	10,023
Pension Benefits	21,445	15,750
Other Postretirement Benefits	4,752	3,996
Accrued Employee Benefits	16,029	15,697
Other Accrued Liabilities	7,758	9,386
Tax Credit and Other Carryforwards	4,733	644
Total	91,833	95,380
Valuation Allowance	(14,614)	(21,629)
Total Deferred Tax Assets	77,219	73,751
Deferred Tax Liabilities
Tax Depreciation in Excess of Book	74,645	77,106
Deferred Tax Liabilities, Intangible Assets	4,259	537
Deferred Tax Liabilities, Other	1,130	6,084
Total Deferred Tax Liabilities	80,034	83,727
Total Net Deferred Tax Liabilities	$ (2,815)	$ (9,976)