CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net income	$ 105,406	$ 266	$ 18,477
Adjustments to reconcile net income to net cash provided by operating activities, net of effects of acquisitions:
Depreciation	86,291	76,883	78,482
Amortization of intangibles	18,353	18,798	20,483
Amortization of debt issuance costs	522	514	1,889
Share-based compensation	20,736	18,609	14,029
Excess tax benefit from share-based compensation			(1,078)
(Gain) loss on disposal of property, plant and equipment	(636)	1,969	1,091
Deferred income taxes	3,674	25,326	(15,978)
Other	(2,335)	(1,814)	1,811
Changes in operating assets:
Accounts receivable	(29,478)	22,261	533
Inventories	(2,154)	(17,199)	5,176
Prepaid expenses and other current assets	(11,119)	1,494	2,456
Changes in operating liabilities:
Accounts payable	9,977	17,313	2,640
Accrued liabilities	(13,445)	13,079	(3,158)
Other liabilities	345	4,495	(8,623)
Income taxes (refundable) payable	(571)	(871)	6,512
Net cash and cash equivalents provided by operating activities	185,566	181,123	124,742
Investing Activities
Acquisitions, net of cash acquired	(41)
Purchases of short-term investments	(15,901)	(12,205)	(23,459)
Sales of short-term investments	12,576	38,600	56,168
Purchases of property, plant and equipment	(87,507)	(111,161)	(58,549)
Proceeds from sales of property, plant and equipment	429	1,219	156
Subsidies and grants		6,968
Other	1,500	(2,333)	(723)
Net cash and cash equivalents used in investing activities	(88,944)	(78,912)	(26,407)
Financing Activities
Advance on lines of credit and short-term debt	9,151	3,375	9,000
Repayments on lines of credit and short-term debt	(2,797)	(2,391)	(9,000)
Taxes related to net share settlement	(11,294)	(278)	(2,528)
Net proceeds from the issuance of common stock	4,862	13,606	120
Excess taxes (paid) benefit from share-based compensation			1,078
Proceeds from long-term debt	465,656	44,500	43,500
Debt issuance costs		(111)	(2,045)
Repayments of long-term debt	(522,473)	(204,374)	(79,913)
Repayments of capital lease obligations	1,198	(587)	(19)
Purchase of treasury stock		(8,745)	(18,014)
Capital contribution from noncontrolling interest	6,255
Dividend distribution to noncontrolling interest	(2,694)	(5,754)	(4,869)
Other	225	2,575	(768)
Net cash and cash equivalents used in financing activities	(51,911)	(158,184)	(63,458)
Effect of exchange rate changes on cash and cash equivalents, including restricted cash	(8,078)	11,461	(4,588)
(Decrease) increase in cash and cash equivalents, including restricted cash	36,633	(44,512)	30,289
Cash and cash equivalents, beginning of year, including restricted cash	205,200	249,712	219,423
Cash and cash equivalents, end of year, including restricted cash	241,833	205,200	249,712
Cash paid during the year for:
Interest	9,962	13,547	11,708
Income taxes	33,265	30,447	17,099
Non-cash activities:
Decrease (increase) property, plant and equipment purchased on accounts payable	$ 7,766	(14,081)	6,393
Noncontrolling Interest
Non-cash activities:
Decrease (increase) in dividend accrued for noncontrolling interest		$ 1,008	$ (1,008)