Income Taxes Income Taxes (Tables)

12 Months Ended

Jun. 30, 2017

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

The provision for income taxes consists of the following:

	Year Ended June 30,
	2017		2016		2015
Current:
Federal	$	80,752	$	66,574	$	70,555
State	9,469		7,571		5,221
Deferred:
Federal	25,756		34,355		28,018
State	5,184		3,169		1,425
	$	121,161	$	111,669	$	105,219

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

The tax effects of temporary differences related to deferred taxes shown on the balance sheets were:

	June 30,
	2017			2016
Deferred tax assets:
Contract and service revenues and costs	$	54,908		$	69,597
Expense reserves (bad debts, insurance, franchise tax and vacation)	14,648			14,770
Net operating loss carryforwards	3,547			3,543
Other, net	2,119			2,090
Total gross deferred tax assets	75,222			90,000
Valuation allowance	(357		)	(608		)
Net deferred tax assets	74,865			89,392
Deferred tax liabilities:
Accelerated tax depreciation	(36,994		)	(40,857		)
Accelerated tax amortization	(178,999		)	(160,719		)
Contract and service revenues and costs	(78,413		)	(76,417		)
Total gross deferred liabilities	(294,406		)	(277,993		)
Net deferred tax liability	$	(219,541	)	$	(188,601	)

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

The following analysis reconciles the statutory federal income tax rate to the effective income tax rates reflected above:

	Year Ended June 30,
	2017		2016		2015
Computed "expected" tax expense	35.0	%	35.0	%	35.0	%
Increase (reduction) in taxes resulting from:
State income taxes, net of federal income tax benefits	2.6	%	1.9	%	1.4	%
Research and development credit	(2.0	)%	(2.5	)%	(1.5	)%
Domestic production activities deduction	(2.1	)%	(1.9	)%	(2.0	)%
Tax over book basis in subsidiary stock	—	%	(1.7	)%	—	%
Tax effects of share-based payments	(0.7	)%	—	%	—	%
Other (net)	0.2	%	0.2	%	0.4	%
	33.0	%	31.0	%	33.3	%

Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Table Text Block]

A reconciliation of the unrecognized tax benefits for the years ended June 30, 2017 and 2016 follows:

	Unrecognized Tax Benefits
Balance at July 1, 2015	$	7,104
Additions for current year tax positions	1,581
Reductions for current year tax positions	(56		)
Additions for prior year tax positions	507
Reductions for prior year tax positions	(38		)
Reductions related to expirations of statute of limitations	(1,677		)
Balance at June 30, 2016	7,421
Additions for current year tax positions	1,457
Reductions for current year tax positions	—
Additions for prior year tax positions	23
Reductions for prior year tax positions	(766		)
Settlements	(1,040		)
Reductions related to expirations of statute of limitations	(1,646		)
Balance at June 30, 2017	$	5,449