Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of income before income tax, domestic and foreign [Table Text Block]

Income before income taxes was attributable to the following sources:

	Year Ended December 31,
	2018		2017			2016
United States	$	37,377	$	38,800		$	35,867
Canada	119		(806		)	1,377
Total	$	37,496	$	37,994		$	37,244

Schedule of components of income tax expense (benefit) [Table Text Block]

The provision for income taxes follows:

	Year Ended December 31,
	2018		2017			2016
Currently payable:
Federal	$	3,165	$	9,914		$	12,216
State	2,290		2,469			2,286
Canadian	50		(262		)	398
Total current	5,505		12,121			14,900
Deferred taxes	4,014		3,753			60
Total taxes on income	$	9,519	$	15,874		$	14,960

Schedule of effective income tax rate reconciliation [Table Text Block]

A reconciliation of the expected statutory U.S. federal rate to our actual effective income tax rate follows:

	Year Ended December 31,
	2018		2017		2016
Statutory U.S. federal tax rate	21.0	%	35.0	%	35.0	%
State income taxes, net of federal benefit	5.7		4.9		4.0
Effect of Canadian income taxes	.1		.3		(.2	)
Nondeductible expenses	2.1		2.2		2.2
ESOP dividend deduction	(.3	)	(.6	)	(.7	)
Uncertain tax adjustments and audit settlement	(3.8	)	(.2	)	.2
Income tax reform - deferred rate remeasurement	—		2.5		—
All other, net	.6		(2.3	)	(.3	)
Effective income tax rate	25.4	%	41.8	%	40.2	%

Deferred tax assets and liabilities, noncurrent [Table Text Block]

Significant components of our noncurrent net deferred tax assets and liabilities at December 31, were as follows:

	December 31,
	2018		2017
Deferred tax assets:
Self-insurance accruals	$	17,579	$	14,186
Accrued compensated absences	1,565		1,747
Accrued expenses and other liabilities	742		798
Accrued stock compensation	1,772		1,571
Defined benefit pension plans	442		2,289
Foreign tax credit carryforward	2,117		605
Other future deductible amounts, net	3,271		3,661
	27,488		24,857
Less deferred tax asset valuation allowance	1,683		—
	25,805		24,857
Deferred tax liabilities:
Intangibles	1,178		969
Prepaid expenses	3,160		2,300
Property and equipment	20,894		16,773
	25,232		20,042
Net deferred tax assets--noncurrent	$	573	$	4,815

Summary of unrecognized income tax benefits [Table Text Block]

The balance of unrecognized benefits and the amount of related interest and penalties at December 31, were as follows:

	December 31,
	2018		2017
Unrecognized tax benefits	$	1,325	$	2,581
Portion, if recognized, would reduce tax expense and effective tax rate	599		1,948
Accrued interest on unrecognized tax benefits	35		128

Schedule of unrecognized tax benefits roll forward [Table Text Block]

The changes in our unrecognized tax benefits are summarized in the table below:

	Year Ended December 31,
	2018			2017			2016
Balance, beginning of year	$	2,581		$	2,532		$	2,557
Additions based on tax positions related to the current year	224			650			402
Additions for tax positions of prior years	20			(21		)	51
Reductions for tax positions of prior years	(1,500		)	—			(39		)
Lapses in statutes of limitations	—			(580		)	(439		)
Balance, end of year	$	1,325		$	2,581		$	2,532