CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities
Net cash provided by operating activities	$ 25,453	$ 38,568
Cash flows from investing activities
Decrease in restricted cash	3	486
Purchases of property, plant and equipment	(13,561)	(23,539)
Proceeds from sales of property, plant, and equipment	19
Purchases of short-term investments	(7,330)	(24,985)
Proceeds from maturity of short-term investments	29,289	10,007
Other	291	(148)
Net cash and cash equivalents provided by (used in) investing activities	8,711	(38,179)
Cash flows from financing activities
Advances on lines of credit and short-term debt		965
Taxes paid related to net share settlement	(2,335)
Repayments on lines of credit and short-term debt		(1,067)
Debt issuance costs	(22)
Proceeds from long-term debt	1,500
Repayments of long-term debt	(15,569)	(23,071)
Net proceeds from issuance of common stock	5	5,649
Repayment of capital lease obligation and other	(843)	(88)
Net cash and cash equivalents used in financing activities	(17,264)	(17,612)
Effect of exchange rate changes on cash and cash equivalents	1,671	(3,664)
Increase (decrease) in cash and cash equivalents	18,571	(20,887)
Cash and cash equivalents, beginning of period	218,435	243,000
Cash and cash equivalents, end of period	237,006	222,113
Non-cash financing activities:
Property, plant and equipment purchased on accounts payable	$ 697	$ (10,281)