Accounts Receivable, Net and Supplemental Balance-Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accounts receivable, net
Accounts receivable	$ 258,569	$ 242,427
Unbilled receivables(1)	110,576	82,605
Accounts receivable, gross	369,145	325,032
Less allowances for credit losses	2,156	3,222
Accounts receivable, net	366,989	321,810
Other current assets
Refundable income taxes	381	14
Prepaid expenses	46,298	32,080
Mitigation bank credit inventory	27,573	6,351
Assets invested for self-insurance	20,658	24,828
Other Receivables, Gross, Current	14,264	18,283
Other	5,518	2,396
Total	114,692	83,952
Property, Plant and Equipment, Net [Abstract]
Land and Land Improvements	25,798	26,023
Buildings and leasehold improvements	92,861	80,768
Equipment	674,020	663,207
Property, Plant and Equipment, Gross	792,679	769,998
Less accumulated depreciation	497,136	501,459
Property and equipment, net	295,543	268,539
Other Assets, Noncurrent [Abstract]
Investment--cost-method affiliate	933	1,258
Deferred income taxes	4,602	6,828
Cloud computing arrangements	474	2,652
Loss Contingency, Receivable	200,000	7,500
Other	4,900	4,603
Other assets	210,909	22,841
Accrued expenses
Employee compensation	36,118	35,536
Accrued compensated absences	14,827	13,034
Self-insured medical claims	2,573	2,806
Income tax payable	8,174	6,573
Customer advances, deposits	2,148	7,736
Taxes, other than income	2,386	5,764
Other	5,549	6,005
Total	71,775	77,454
Other current liabilities
Other Sundry Liabilities, Current	6,106	0
Current operating lease liabilities	37,972	34,652
Current portion of long-term debt	48,875	23,826
Self-insurance accruals	54,486	56,221
Total	98,564	90,873
Other noncurrent liabilities
Non-qualified retirement plans	5,465	8,336
Estimated Litigation Liability, Noncurrent	200,000	7,500
Other	7,553	8,184
Other noncurrent liabilities	$ 213,018	$ 24,020