Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net income	$ 246,477	$ 120,637
Depreciation and amortization	274,991	248,036
Other operating activities and non-cash items	305	10,151
Changes in assets and liabilities	(65,442)	(136,422)
Net cash provided by operating activities	456,331	242,402
Cash flows from investing activities:
Payments for property, plant and equipment	(273,617)	(134,340)
Proceeds from sale of property, plant and equipment	2,249	2,389
Proceeds from foreign exchange forward contracts	10,553	11,557
Payments for foreign exchange forward contracts	(37,972)	(10,595)
Payments for short-term investments	(173,307)	(325,632)
Proceeds from sale of short-term investments	45,396	8,593
Proceeds from maturities of short-term investments	103,116	13,072
Other investing activities	2,087	(157)
Net cash used in investing activities	(321,495)	(435,113)
Cash flows from financing activities:
Proceeds from revolving credit facilities	0	282,000
Payments of revolving credit facilities	0	(216,000)
Proceeds from short-term debt	3,679	62,495
Payments of short-term debt	(10,431)	(66,609)
Proceeds from issuance of long-term debt	120,992	225,985
Payments of long-term debt	(184,212)	(201,425)
Payments of finance lease obligations	(6,633)	(4,876)
Payments of dividends	(29,221)	0
Other financing activities	8,287	972
Net cash (used in) provided by financing activities	(97,539)	82,542
Effect of exchange rate fluctuations on cash, cash equivalents and restricted cash	(10,274)	(1,177)
Net increase (decrease) in cash, cash equivalents and restricted cash	27,023	(111,346)
Cash, cash equivalents and restricted cash, beginning of period	702,197	898,532
Cash, cash equivalents and restricted cash, end of period	729,220	787,186
Non-cash investing and financing activities:
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	40,734	1,853
Property, plant and equipment included in capital expenditures payable	460,451	259,520
Right of use assets acquired through operating lease liabilities	$ 24,194	$ 17,293