CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating Activities:
Net income	$ 47,928	$ 20,305
Adjustments to reconcile net income to cash from operating activities:
Depreciation and amortization	21,536	18,312
Stock-based compensation expense	5,327	5,740
Deferred income taxes	4,813	8,825
Equity in undistributed income of unconsolidated joint ventures	(1,976)	(1,321)
Dividends received from unconsolidated joint ventures	616	426
Pension and postretirement benefits	(794)	(1,404)
Loss (gain) from the sale of property, plant and equipment	(942)	15
Bad debt expense	61	0
Proceeds from insurance related to operations	826	0
Changes in operating assets and liabilities, excluding effects of acquisitions:
Accounts receivable	(13,220)	(8,693)
Inventories	(6,464)	616
Pension contribution	(147)	(138)
Other current assets	(1,991)	(2,056)
Accounts payable and other accrued expenses	7,213	12,585
Other, net	1,703	(1,908)
Net cash provided by operating activities	64,489	51,304
Investing Activities:
Business acquisition	(60,191)	0
Capital expenditures, net	(9,696)	(9,992)
Proceeds from insurance related to property, plant and equipment	922
Proceeds from the sale of property, plant and equipment, net	1,641
Net cash used in investing activities	(67,324)	(9,992)
Financing Activities:
Debt issuance costs	(1,169)	0
Repayment of debt principal and long term lease obligation	(50,178)	(1,516)
Repurchases of capital stock		(3,997)
Proceeds from the exercise of stock options, net	1,905	2,058
Issuance of shares upon vesting of restricted stock units, net	(2,617)	(1,201)
Proceeds from issuance of shares to employee stock purchase plan	422	427
Net cash used in financing activities	(51,637)	(4,229)
Effect of exchange rate fluctuations on cash	4,017	5,728
Net increase (decrease) in cash and cash equivalents	(50,455)	42,811
Cash and cash equivalents at beginning of period	227,767	204,586
Cash and cash equivalents at end of period	$ 177,312	$ 247,397