CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net income	$ 108,133	$ 49,990	$ 47,319
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	43,284	71,425	49,162
Equity compensation expense	16,994	13,532	12,305
Deferred income taxes	(3,195)	(13,406)	(17,549)
Equity in undistributed income of unconsolidated joint ventures	(7,032)	(4,877)	(5,319)
Dividends received from unconsolidated joint ventures	4,965	7,075	5,375
Pension settlement charges	534	(63)	53,213
Pension and other postretirement benefits	(471)	(160)	(943)
Asbestos-related provision (benefit)	(220)	(682)	1,720
(Gain) loss on sale or disposal of property, plant and equipment	(880)	41	756
Impairment charges	455	639	1,537
UTIS fire fixed asset and inventory write-offs	1,947	0	0
Provision (benefit) for credit losses	(279)	223	437
Changes in assets and liabilities:
Accounts receivable	(26,197)	(8,934)	20,677
Proceeds from insurance/government subsidies related to operations	400	0	0
Contract assets	(10,035)	(4,120)	273
Inventories	(34,413)	34,687	(1,200)
Pension and postretirement benefit contributions	(160)	(253)	(103)
Other current assets	1,723	(217)	(1,519)
Accounts payable and other accrued expenses	36,688	10,084	(9,139)
Other, net	(7,878)	10,072	4,321
Net cash provided by operating activities	124,363	165,056	161,323
Investing Activities:
Acquisition of business, net of cash received	(168,204)	0	0
Capital expenditures	(71,125)	(40,385)	(51,597)
Proceeds from the sale of property, plant and equipment, net	714	0	9
Return of capital from unconsolidated joint ventures	0	0	2,625
Net cash used in investing activities	(238,615)	(40,385)	(48,963)
Financing Activities:
Proceeds from borrowings under revolving credit facility	190,000	150,000	0
Line of credit issuance costs	0	(1,862)	0
Repayment of debt principal and finance lease obligations	(29,624)	(248,330)	(105,886)
Payments of taxes related to net share settlement of equity awards	(2,881)	(5,357)	(7,550)
Proceeds from the exercise of stock options, net	0	0	344
Proceeds from issuance of shares to employee stock purchase plan	1,562	1,360	1,249
Net cash (used in) provided by financing activities	159,057	(104,189)	(111,843)
Effect of exchange rate fluctuations on cash	(4,294)	4,454	(1,406)
Net increase (decrease) in cash and cash equivalents	40,511	24,936	(889)
Cash and cash equivalents at beginning of period	191,785	166,849	167,738
Cash and cash equivalents at end of period	232,296	191,785	166,849
Supplemental Disclosures:
Accrued capital additions	10,903	715	3,420
Interest, net of amounts capitalized	2,402	7,251	7,762
Income taxes	$ 33,788	$ 29,983	$ 17,593