Income Taxes (Tables)

12 Months Ended

Jun. 30, 2012

Income Tax Disclosure [Abstract]

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

	Year ended June 30,
	2012		2011		2010
Current:
Federal	$	48,053	$	43,334	$	39,994
State	6,022		6,180		6,238
Deferred:
Federal	20,649		18,276		14,327
State	1,960		2,251		2,367
	$	76,684	$	70,041	$	62,926

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

	June 30,
	2012			2011
Deferred tax assets:
Deferred revenue	$	8,575		$	5,372
Expense reserves (bad debts, insurance, franchise tax and vacation)	9,349			8,086
Net operating loss carryforwards	9,454			11,097
Other, net	1,410			1,122
	28,788			25,677
Deferred tax liabilities:
Accelerated tax depreciation	(34,636		)	(29,971		)
Accelerated tax amortization	(91,379		)	(81,265		)
Prepaid expenses	(23,331		)	(18,713		)
Other, net	(6,280		)	—
	(155,626		)	(129,949		)
Net deferred tax liability before valuation allowance	(126,838		)	(104,272		)
Valuation allowance	(350		)	(306		)
Net deferred tax liability	$	(127,188	)	$	(104,578	)

	2012			2011
Deferred income taxes (current)	$	(26,256	)	$	(15,274	)
Deferred income taxes (long-term)	(100,932		)	(89,304		)
	$	(127,188	)	$	(104,578	)

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

	Year Ended June 30,
	2012		2011		2010
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	2.2	%	2.6	%	2.5	%
Research and development credit	(1.8	)%	(2.0	)%	(0.7	)%
Domestic production activities deduction	(2.1	)%	(2.5	)%	(3.0	)%
Other (net)	(0.2	)%	0.7	%	1.0	%
	33.1	%	33.8	%	34.8	%

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

	Unrecognized Tax Benefits
Balance at July 1, 2010	$	7,187
Additions for current year tax positions	1,338
Reductions for current year tax positions	—
Additions for prior year tax positions	599
Reductions for prior year tax positions	—
Settlements	—
Reductions related to expirations of statute of limitations	(227		)
Balance at June 30, 2011	8,897
Additions for current year tax positions	1,673
Reductions for current year tax positions	—
Additions for prior year tax positions	8
Reductions for prior year tax positions	(2,904		)
Settlements	(1,454		)
Reductions related to expirations of statute of limitations	(18		)
Balance at June 30, 2012	$	6,202