Income Taxes (Tables)

12 Months Ended

Apr. 30, 2017

Schedule of Components of Income Tax Expense (Benefit)

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



	Years ended April 30,
	2017		2016		2015
Current tax expense
Federal	$	41,300	$	58,273	$	49,593
State	5,693		8,959		7,093
	46,993		67,232		56,686
Deferred tax expense	45,190		55,492		44,711
Total income tax expense	$	92,183	$	122,724	$	101,397

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,
	2017			2016
Deferred tax assets
Accrued liabilities and reserves	$	10,948		$	11,522
Property and equipment depreciation	16,604			15,914
Workers compensation	10,934			10,540
Deferred compensation	5,916			6,696
Equity compensation	6,923			5,186
State net operating losses & tax credits	938			973
Other	1,275			1,582
Total gross deferred tax assets	53,538			52,413
Less valuation allowance	60			84
Total net deferred tax assets	53,478			52,329
Deferred tax liabilities
Property and equipment depreciation	(468,470		)	(425,586		)
Goodwill	(25,052		)	(21,677		)
Other	(80		)	—
Total gross deferred tax liabilities	(493,602		)	(447,263		)
Net deferred tax liability	$	(440,124	)	$	(394,934	)

Schedule of Effective Income Tax Rate Reconciliation



	Years ended April 30,
	2017		2016		2015
Income taxes at the statutory rates	35.0	%	35.0	%	35.0	%
Federal tax credits	(1.8	)%	(1.7	)%	(1.7	)%
State income taxes, net of federal tax benefit	2.8	%	2.7	%	3.1	%
ASU 2016-09 Benefit (share based compensation)	(1.3	)%	—	%	—	%
Other	(0.5	)%	(0.8	)%	(0.4	)%
	34.2	%	35.2	%	36.0	%

Schedule of Unrecognized Tax Benefits

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



	2017			2016
Beginning balance	$	6,484		$	8,043
Additions based on tax positions related to current year	1,705			1,084
Additions for tax positions of prior years	—			26
Reductions for tax positions of prior years	—			—
Reductions due to lapse of applicable statute of limitations	(2,827		)	(2,669		)
Settlements	—			—
Ending balance	$	5,362		$	6,484