Income Taxes - Components of the Temporary Differences (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020
Deferred Tax Assets: [Abstract]
Postretirement benefits	$ 9,364	$ 20,232
Accrued liabilities	7,314	3,970
Net operating loss carryforward	48,195	38,754
Deferred Tax Assets, Goodwill and Intangible Assets	7,377	9,482
Operating lease liabilities	6,592	5,419
Other	6,292	6,893
Total deferred tax assets	85,134	84,750
Deferred tax liabilities: [Abstract]
Fixed assets	(15,448)	(13,427)
Right-of-use operating lease assets	6,606	5,513
Other	72	(2,950)
Total deferred tax liabilities	(21,982)	(21,890)
Valuation allowance	(64,312)	(64,354)
Deferred Tax Liabilities, Net	$ (1,160)	$ (1,494)