Deferred Tax Liability (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Contract and service revenues and costs	$ 18,606	$ 54,908
Expense reserves (bad debts, insurance, franchise tax and vacation)	11,164	14,648
Net operating loss carryforwards	2,759	3,547
Other, net	2,711	2,119
Total gross deferred tax assets	35,240	75,222
Valuation allowance	(515)	(357)
Net deferred tax assets	34,725	74,865
Accelerated tax depreciation	(32,026)	(36,994)
Accelerated tax amortization	(141,274)	(178,999)
Contract and service revenues and costs	(51,038)	(78,413)
Total gross deferred liabilities	224,338	294,406
Net deferred tax liability	$ (189,613)	$ (219,541)