Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income before income taxes
Income before income taxes	$ 97,236	$ 85,199	$ 89,447
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	97,237	85,199	89,447
Provision for income taxes
Federal	17,708	18,795	18,101
State	6,275	7,173	7,221
Canadian	(62)	11	78
Total current	23,921	25,979	25,400
Deferred taxes	1,175	(2,070)	(1,652)
Total taxes on income	$ 25,096	$ 23,909	$ 23,748
Tax rate reconciliation
Statutory U.S. federal tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	5.40%	6.10%	5.50%
Effect of Canadian income taxes	0.00%	(0.20%)	0.10%
Nondeductible expenses	0.70%	1.90%	1.50%
Stock compensation	(0.80%)	(0.80%)	(0.90%)
ESOP dividend deduction	(0.20%)	(0.20%)	(0.10%)
Uncertain tax adjustments and audit settlement	0.10%	0.00%	(0.50%)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	(0.30%)	0.00%	0.00%
Other, net	(0.10%)	0.40%	0.00%
Effective income tax rate	25.80%	28.20%	26.60%
Noncurrent deferred tax assets and liabilities, net
Self-insurance accruals	$ 28,198	$ 28,183
Accrued compensated absences	2,451	1,931
Accrued expenses and other liabilities	880	808
Accrued stock compensation	4,093	3,298
Foreign tax credit carryforward	1,359	1,569
Lease obligations	21,958	20,938
Deferred Tax Assets, Goodwill and Intangible Assets	81	0
Other future deductible amounts, net	5,236	5,988
Deferred tax assets, gross,noncurrent	64,256	62,715
Less deferred tax asset valuation allowance	864	1,185
Deferred tax assets, net--noncurrent	63,392	61,530
Intangibles	0	652
Prepaid expenses	5,874	5,142
Lease right of use assets	21,986	21,177
Property and equipment	29,531	27,731
Deferred tax liabilities, gross, noncurrent	57,391	54,702
Net deferred tax asset--noncurrent	6,001	6,828
Undistributed earnings of foreign subsidiaries	23,830
Unrecognized benefits and related interest and penalties
Unrecognized tax benefits	1,022	638	$ 700
Portion, if recognized, would reduce tax expense and effective tax rate	369	311
Accrued interest on unrecognized tax benefits	47	53
Reconciliation of unrecognized tax benefits
Balance, beginning of year	638	700	1,183
Additions based on tax positions related to the current year	(436)	(24)	(4)
Additions for tax positions of prior years	39	0	0
Reductions for tax positions of prior years	0	8	13
Lapses in statutes of limitations	(91)	(78)	(474)
Balance, end of year	1,022	638	700
United States
Income before income taxes
Income before income taxes	99,116	90,379	89,086
Canada
Income before income taxes
Income before income taxes	$ (1,879)	$ (5,180)	$ 361