CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Cash flows from operating activities	$ 106,340	$ 74,935
Cash flows from investing activities
Decrease (increase) in restricted cash	555	(311)
Purchases of property, plant and equipment	(81,877)	(47,054)
Purchases of short-term investments	(9,744)	(17,482)
Proceeds from maturity of short-term investments	27,891	46,352
Other	(1,238)	(1,316)
Net cash and cash equivalents used in investing activities	(64,413)	(19,811)
Cash flows from financing activities
Advances on lines of credit and short-term debt	2,383	9,000
Taxes paid related to net share settlement	(277)	(2,528)
Repayments on lines of credit and short-term debt	(395)	(9,000)
Debt issuance costs	(99)	(435)
Proceeds from long-term debt	7,500	23,500
Repayments of long-term debt	(109,607)	(70,714)
Net proceeds from issuance of common stock	6,880	5
Repayment of capital lease obligation	(533)	(19)
Dividend distribution to noncontrolling interest	(5,754)	(4,615)
Other	2,056	518
Net cash and cash equivalents used in financing activities	(97,846)	(54,288)
Effect of exchange rate changes on cash and cash equivalents	9,343	1,255
Change in cash and cash equivalents	(46,576)	2,091
Cash and cash equivalents, beginning of period	247,802	218,435
Cash and cash equivalents, end of period	201,226	220,526
Non-cash financing activities:
Decrease (increase) in accounts payable related to the purchase of property, plant and equipment	$ (10,919)	$ 7,459