Accounts Receivable, Net and Supplemental Balance Sheet Information (Tables)

12 Months Ended

Dec. 31, 2023

Accounts Receivable, Net and Supplemental Balance Sheet Information [Abstract]

Schedule of accounts receivable [Table Text Block]

Accounts receivable, net, consisted of the following:

	December 31,
Accounts receivable, net	2023		2022
Accounts receivable	$	263,426	$	242,427
Unbilled receivables (1)	99,485		82,605
	362,911		325,032
Less allowances for credit losses	2,441		3,222
Total	$	360,470	$	321,810

Schedule of other current assets [Table Text Block]

The following items comprised the amounts included in the balance sheets:

	December 31,
Other current assets	2023		2022
Refundable income taxes	$	—	$	14
Mitigation bank credit inventory	28,385		6,351
Assets invested for self-insurance	20,959		24,828
Payroll taxes refundable	22,591		18,283
Other	302		2,396
Total	$	72,237	$	51,872

Property, plant and equipment [Table Text Block]

Depreciation is computed for financial reporting purposes by the straight-line method for land improvements, building and leasehold improvements and by the declining-balance method for equipment, based on the estimated useful lives of the assets, as follows:

Land improvements	5 to 20 years
Buildings	5 to 30 years
Equipment	3 to 20 years
Leasehold improvements	Shorter of lease term or estimated useful life; ranging from 5 to 20 years

	December 31,
Property and equipment, net	2023		2022
Land and land improvements	$	28,177	$	26,023
Buildings and leasehold improvements	99,964		80,768
Equipment	684,562		663,207
	812,703		769,998
Less accumulated depreciation	500,025		501,459
Total	$	312,678	$	268,539

Schedule of other assets, noncurrent [Table Text Block]

	December 31,
Other assets, noncurrent	2023		2022
Investment--cost-method affiliate	$	1,405	$	1,258
Deferred income taxes	6,001		6,828
Cloud computing arrangements	107		2,652
Other	4,362		4,603
Total	$	11,875	$	15,341

Schedule of accrued expenses [Table Text Block]

	December 31,
Accrued expenses	2023		2022
Employee compensation	$	40,656	$	35,536
Accrued compensated absences	14,483		13,034
Self-insured medical claims	2,309		2,806
Customer advances, deposits	1,275		7,736
Income taxes payable	1,135		6,573
Taxes, other than income	6,017		5,764
Other	16,069		6,005
Total	$	81,944	$	77,454

Schedule of other liabilities, noncurrent [Table Text Block]

	December 31,
Other liabilities, noncurrent	2023		2022
Pension and retirement plans	$	5,630	$	8,336
Other	6,096		8,184
Total	$	11,726	$	16,520