Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]

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

Deferred tax assets and liabilities as of December 31 are as follows:

	2018		2017
	(in thousands)
Deferred income tax assets:
Allowance for doubtful accounts	$	224	$	515
Accrued expenses	3,179		6,550
Stock-based compensation	92		156
Insurance accruals	15,415		18,225
State net operating loss carryforward	—		237
Indirect tax benefits of unrecognized tax benefits	963		1,278
Other	2		—
Total gross deferred tax assets	19,875		26,961
Less valuation allowance	—		—
Net deferred tax assets	19,875		26,961
Deferred income tax liabilities:
Property and equipment	(74,794)		(81,322)
Goodwill	(10,319)		(7,984)
Prepaid expenses	(1,268)		(1,406)
	(86,381)		(90,712)
Net deferred tax liability	$	(66,506)	$	(63,751)

The deferred tax amounts above have been classified in the accompanying consolidated balance sheets at December 31, 2018 and 2017 as follows:

	2018		2017
	(in thousands)
Noncurrent assets, net	$	4,535	$	1,737
Long-term liabilities, net	(71,041)		(65,488)
	$	(66,506)	$	(63,751)

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

Income tax expense consists of the following:

	2018		2017		2016
	(in thousands)
Current income taxes:
Federal	$	11,985	$	17,997	$	34,664
State	4,498		(1,495)		454
	16,483		16,502		35,118
Deferred income taxes:
Federal	5,537		(28,020)		(5,291)
State	(2,780)		843		(164)
	2,757		(27,177)		(5,455)
Total	$	19,240	$	(10,675)	$	29,663

The income tax provision differs from the amount determined by applying the U.S. federal tax rate as follows:

	2018		2017		2016
	(in thousands)
Federal tax at statutory rate (21%, 35%, 35% respectively)	$	19,302	$	22,574	$	30,117
State taxes, net of federal benefit	2,200		178		1,135
Permanent differences to return	408		309		(23)
Return to provision adjustment	(1,327)		(325)		(362)
Uncertain income tax penalties and interest, net	(1,067)		(1,208)		(1,473)
Enacted federal tax rate change	—		(32,789)		—
Other	(276)		586		269
	$	19,240	$	(10,675)	$	29,663

Reconciliation of Unrecognized Tax Benefits [Table Text Block]

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

	2018		2017
	(in thousands)
Balance at January 1,	$	5,839	$	8,751
Additions based on tax positions related to current year	700		135
Reductions for tax positions of prior years	—		(331)
Reductions due to lapse of applicable statute of limitations	(1,954)		(2,699)
Settlements	—		(17)
Balance at December 31,	$	4,585	$	5,839