Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net loss	$ (1,105,366)	$ (282,444)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	243,208	263,844
Loss on impairment of assets	774,028
Reorganization items, net	22,107
(Gain) loss on disposition of assets	(4,132)	1,191
Deferred tax provision	(16,865)	(48,323)
Stock-based compensation expense	5,637	4,533
Contract liabilities, net	9,814	15,060
Contract assets, net	3,048	302
Deferred contract costs, net	(2,578)	49,866
Long-term employee remuneration programs	(4,803)	1,609
Noncurrent collateral deposits	(18,262)
Other assets, noncurrent	(8,513)	180
Other liabilities, noncurrent	(3,240)	(90)
Other	2,964	799
Changes in operating assets and liabilities:
Accounts receivable	107,148	(27,177)
Prepaid expenses and other current assets	3,957	(128)
Accounts payable and accrued liabilities	(10,440)	7,115
Taxes payable	9,728	(548)
Net cash provided by (used in) operating activities	7,440	(14,211)
Investing activities:
Capital expenditures	(162,621)	(249,819)
Proceeds from sale of foreign bonds	5,915
Proceeds from maturities of marketable securities		2,300,000
Purchase of marketable securities		(1,996,996)
Proceeds from disposition of assets, net of disposal costs	5,378	16,097
Net cash (used in) provided by investing activities	(151,328)	69,282
Financing activities:
Borrowings under credit facility	436,000
Other		(12)
Net cash provided by (used in) financing activities	436,000	(12)
Net change in cash, cash equivalents and restricted cash	292,112	55,059
Cash, cash equivalents and restricted cash, beginning of period	156,281	154,073
Cash, cash equivalents and restricted cash, end of period	$ 448,393	$ 209,132