Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
OPERATING ACTIVITIES
Net income	$ 96,508	$ 118,768	$ 97,243
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	62,480	65,130	63,328
Amortization	6,569	9,125	9,377
Change in deferred taxes and other liabilities	(8,496)	12,181	11,101
Impairment of property, plant, equipment, and inventory	1,808	856	1,173
Non-cash interest expense	1,118	875	(290)
Non-cash portion of pension settlement expense	42,657	0	411
Compensation and benefits paid or payable in Class A Common Stock	4,527	3,146	1,505
Provision/(recovery) for credit losses from uncollected receivables and contract assets	1,408	(1,299)	1,628
Foreign currency remeasurement (gain)/loss on intercompany loans	(4,434)	(3,150)	14,246
Fair value adjustment on foreign currency options	(509)	169	0
Changes in operating assets and liabilities that provided/(used) cash:
Accounts receivable	(14,301)	(7,734)	31,522
Contract assets	(36,434)	25,446	(59,122)
Inventories	(24,541)	(9,942)	(13,685)
Prepaid expenses and other current assets	(4,134)	(998)	(7,811)
Income taxes prepaid and receivable	(6,005)	3,944	113
Accounts payable	8,572	9,492	(15,586)
Accrued liabilities	3,226	(774)	(3,856)
Income taxes payable	183	(477)	5,939
Noncurrent receivables	3,911	4,355	4,158
Other noncurrent liabilities	(10,133)	(13,713)	(2,437)
Other, net	4,234	2,075	1,296
Net cash provided by operating activities	128,214	217,475	140,253
INVESTING ACTIVITIES
Purchases of property, plant and equipment	(93,675)	(52,793)	(41,463)
Purchased software	(2,673)	(906)	(927)
Net cash used in investing activities	(96,348)	(53,699)	(42,390)
FINANCING ACTIVITIES
Proceeds from borrowings	162,000	8,000	75,000
Principal payments on debt	(73,000)	(56,009)	(101,020)
Principal payments on finance lease liabilities	(654)	(1,438)	(7,214)
Debt acquisition costs	0	0	(2,432)
Purchase of Treasury shares	(84,780)	(23,449)	0
Taxes paid in lieu of share issuance	(770)	(998)	(490)
Proceeds from options exercised	17	153	55
Dividends paid	(26,465)	(25,894)	(24,568)
Net cash used in financing activities	(23,652)	(99,635)	(60,669)
Effect of exchange rate changes on cash and cash equivalents	(18,474)	(3,421)	8,582
Increase/(decrease) in cash and cash equivalents	(10,260)	60,720	45,776
Cash and cash equivalents at beginning of period	302,036	241,316	195,540
Cash and cash equivalents at end of period	$ 291,776	$ 302,036	$ 241,316