Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (449,636)	$ (56,256)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization expense	75,306	94,800
Impairments of goodwill	406,056	0
Impairments of inventories	31,151	0
Impairments of fixed assets	8,190	33,697
Stock-based compensation expense	5,346	12,822
Amortization of debt discount and deferred financing costs	5,937	5,903
Deferred income tax benefit	(16,915)	(11,935)
Gains on extinguishment of 1.50% convertible senior notes	(10,721)	0
Gains on disposals of assets	(2,088)	(2,310)
Other, net	3,732	1,216
Changes in operating assets and liabilities:
Accounts receivable	67,371	24,993
Inventories	9,174	(6,867)
Accounts payable and accrued liabilities	(39,594)	3,143
Income taxes payable	248	1,948
Deferred revenue	31,114	11,793
Other operating assets and liabilities, net	6,471	2,947
Net cash flows provided by operating activities	131,142	115,894
Cash flows from investing activities:
Capital expenditures	(11,277)	(45,832)
Proceeds from disposition of property, plant and equipment	8,984	3,619
Other, net	(444)	(1,534)
Net cash flows used in investing activities	(2,737)	(43,747)
Cash flows from financing activities:
Revolving credit facility borrowings	72,173	175,306
Revolving credit facility repayments	(105,104)	(246,450)
Purchases of 1.50% convertible senior notes	(20,078)	(858)
Other debt and finance lease repayments, net	(337)	(434)
Payment of financing costs	(962)	(18)
Shares added to treasury stock as a result of net share settlements due to vesting of stock awards	(2,675)	(3,698)
Purchases of treasury stock	0	(757)
Net cash flows used in financing activities	(56,983)	(76,909)
Effect of exchange rate changes on cash and cash equivalents	(214)	101
Net change in cash and cash equivalents	71,208	(4,661)
Cash and cash equivalents, beginning of period	8,493	19,316
Cash and cash equivalents, end of period	79,701	14,655
Cash paid (received) for:
Interest	5,716	8,378
Income taxes, net	$ (37,393)	$ (2,522)