Income Taxes (Tables)

12 Months Ended

Apr. 30, 2016

Schedule of Components of Income Tax Expense (Benefit)

Income tax expense attributable to earnings consisted of the following components:



	Years ended April 30,
	2016		2015		2014
Current tax expense
Federal	$	58,273	$	49,593	$	44,078
State	8,959		7,093		5,657
	67,232		56,686		49,735
Deferred tax expense	55,492		44,711		17,089
Total income tax expense	$	122,724	$	101,397	$	66,824

Schedule of Deferred Tax Assets and Liabilities

The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and deferred tax liabilities were as follows:



	As of April 30,
	2016			2015
Deferred tax assets
Accrued liabilities and reserves	$	11,522		$	8,593
Property and equipment depreciation	15,914			12,846
Workers compensation	10,540			9,536
Deferred compensation	6,696			6,653
Equity compensation	5,186			3,767
State net operating losses & tax credits	973			626
Other	1,582			1,787
Total gross deferred tax assets	52,413			43,808
Less valuation allowance	84			228
Total net deferred tax assets	52,329			43,580
Deferred tax liabilities
Property and equipment depreciation	(425,586		)	(363,965		)
Goodwill	(21,677		)	(18,319		)
Other	—			(738		)
Total gross deferred tax liabilities	(447,263		)	(383,022		)
Net deferred tax liability	$	(394,934	)	$	(339,442	)

Schedule of Effective Income Tax Rate Reconciliation



	Years ended April 30,
	2016		2015		2014
Income taxes at the statutory rates	35.0	%	35.0	%	35.0	%
Federal tax credits	(1.7	)%	(1.7	)%	(2.1	)%
State income taxes, net of federal tax benefit	2.7	%	3.1	%	3.2	%
Out of period adjustments	—	%	—	%	(1.4	)%
Other	(0.8	)%	(0.4	)%	(0.2	)%
	35.2	%	36.0	%	34.5	%

Schedule of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:



	2016			2015
Beginning balance	$	8,043		$	9,244
Additions based on tax positions related to current year	1,084			1,186
Additions for tax positions of prior years	26			13
Reductions for tax positions of prior years	—			—
Reductions due to lapse of applicable statute of limitations	(2,669		)	(2,400		)
Settlements	—			—
Ending balance	$	6,484		$	8,043