Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ 120,637	$ (31,674)
Depreciation and amortization	248,036	268,819
Other operating activities and non-cash items	10,151	33,112
Changes in assets and liabilities	(136,422)	(101,329)
Net cash provided by operating activities	242,402	168,928
Cash flows from investing activities:
Payments for property, plant and equipment	(134,340)	(273,672)
Proceeds from sale of property, plant and equipment	2,389	8,247
Proceeds from insurance recovery for property, plant and equipment	0	1,538
Proceeds from sale of short-term investments	8,593	0
Proceeds from maturities of short-term investments	13,072	6,469
Payments for short-term investments	(325,632)	(5,935)
Other investing activities	805	2,330
Net cash used in investing activities	(435,113)	(261,023)
Cash flows from financing activities:
Proceeds from revolving credit facilities	282,000	85,000
Repayments of revolving credit facilities	(216,000)	(5,000)
Proceeds from short-term debt	62,495	29,781
Payments of short-term debt	(66,609)	(25,548)
Proceeds from issuance of long-term debt	225,985	614,375
Payments of long-term debt	(201,425)	(732,178)
Payments of finance lease obligations	(4,876)	(2,746)
Other financing activities	972	(3,865)
Net cash provided by (used in) financing activities	82,542	(40,181)
Effect of exchange rate fluctuations on cash, cash equivalents and restricted cash	(1,177)	1,131
Net decrease in cash, cash equivalents and restricted cash	(111,346)	(131,145)
Cash, cash equivalents and restricted cash, beginning of period	898,532	688,051
Cash, cash equivalents and restricted cash, end of period	787,186	556,906
Non-cash investing and financing activities:
Property, plant and equipment included in capital expenditures payable	$ 259,520	$ 135,126