CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating Activities:
Net income	$ 76,079	$ 63,199
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	37,176	35,320
Equity compensation expense	9,294	8,536
Deferred income taxes	(5,565)	(17)
Equity in undistributed income of unconsolidated joint ventures	(4,077)	(4,453)
Dividends received from unconsolidated joint ventures	5,375	4,431
Pension and other postretirement benefits	(503)	(1,193)
Asbestos-related charges	67	0
Loss (gain) on sale or disposal of property, plant and equipment	278	(161)
Impairment charges	1,537	477
Provision (benefit) for doubtful accounts	16	(264)
Changes in assets and liabilities:
Accounts receivable	3,668	(14,012)
Contract assets	(1,342)	(20,260)
Inventories	(7,788)	(11,840)
Pension and postretirement benefit contributions	(16)	(25,347)
Other current assets	641	146
Accounts payable and other accrued expenses	(2,552)	(4,354)
Other, net	3,384	3,216
Net cash provided by operating activities	115,672	33,424
Investing Activities:
Acquisition of business, net of cash received	0	(78,571)
Isola asset acquisition	0	(43,434)
Capital expenditures	(38,827)	(36,557)
Proceeds from the sale of property, plant and equipment, net	9	1,027
Return of capital from unconsolidated joint ventures	2,625	0
Net cash used in investing activities	(36,193)	(157,535)
Financing Activities:
Proceeds from borrowings under revolving credit facility	0	102,500
Repayment of debt principal and finance lease obligations	(98,294)	(1,046)
Payments of taxes related to net share settlement of equity awards	(7,309)	(6,492)
Proceeds from the exercise of stock options, net	344	734
Proceeds from issuance of shares to employee stock purchase plan	1,249	1,082
Share repurchases	0	(2,999)
Net cash (used in) provided by financing activities	(104,010)	93,779
Effect of exchange rate fluctuations on cash	(2,460)	(1,271)
Net decrease in cash and cash equivalents	(26,991)	(31,603)
Cash and cash equivalents at beginning of period	167,738	181,159
Cash and cash equivalents at end of period	140,747	149,556
Supplemental Disclosures:
Accrued capital additions	1,999	2,099
Interest, net of amounts capitalized	6,449	4,662
Income taxes	$ 16,018	$ 23,357