CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating Activities:
Net income	$ 63,199	$ 73,460
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	35,320	32,679
Equity compensation expense	8,536	8,508
Deferred income taxes	(17)	10,452
Equity in undistributed income of unconsolidated joint ventures	(4,453)	(3,359)
Dividends received from unconsolidated joint ventures	4,431	616
Pension and postretirement benefits	(1,193)	(1,177)
Realized (gain) loss from sale of property, plant and equipment	(161)	(5,329)
Impairment of assets/investments	477	341
(Benefit) provision for doubtful accounts	(264)	(553)
Proceeds from insurance related to operations	0	932
Changes in operating assets and liabilities, excluding effects of acquisitions:
Accounts receivable	(14,012)	(12,772)
Contract assets	(20,260)	0
Inventories	(11,840)	(16,573)
Pension and postretirement benefit contributions	(25,347)	(372)
Other current assets	146	(1,283)
Accounts payable and other accrued expenses	(4,354)	13,325
Other, net	3,216	956
Net cash provided by operating activities	33,424	99,851
Investing Activities:
Acquisition of business, net of cash received	(78,571)	(60,191)
Capital expenditures	(36,557)	(17,678)
Isola asset acquisition	(43,434)	0
Proceeds from insurance claims	0	1,040
Proceeds from the sale of property, plant and equipment, net	1,027	8,130
Net cash used in investing activities	(157,535)	(68,699)
Financing Activities:
Proceeds from long-term borrowings	102,500	0
Line of credit issuance costs	0	(1,169)
Repayment of debt principal and capital lease obligations	(1,046)	(110,285)
Repurchases of capital stock	(2,999)	0
Proceeds from the exercise of stock options, net	734	1,926
Payments of taxes related to net share settlement of equity awards	(6,492)	(5,145)
Proceeds from issuance of shares to employee stock purchase plan	1,082	895
Net cash provided by (used in) financing activities	93,779	(113,778)
Effect of exchange rate fluctuations on cash	(1,271)	5,852
Net decrease in cash and cash equivalents	(31,603)	(76,774)
Cash and cash equivalents at beginning of period	181,159	227,767
Cash and cash equivalents at end of period	149,556	150,993
Supplemental Disclosures:
Interest, net of amounts capitalized	4,662	4,539
Income taxes	$ 23,357	$ 23,989