Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities:
Net loss	$ (67,318)	$ (24,075)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	38,775	38,598
Deferred income taxes	(7,407)	(7,446)
(Gain) loss on asset dispositions	(44)	708
Equity in (income) loss of unconsolidated affiliate, net	(2,400)	(45)
Inventory valuation reserves	1,416	3,308
Changes in operating assets and liabilities	13,301	(5,638)
Net cash (used in) provided by operating activities	(23,677)	5,410
Investing activities:
Purchase of property and equipment	(8,970)	(18,098)
Proceeds from asset dispositions	1,235	1,453
Purchase of short-term investments	(183,421)	(260,996)
Proceeds from sale of short-term investments	121,512	264,918
Payment of deposit on aircraft	(50)	0
Refund of deposit on aircraft	503	0
Loan to unconsolidated affiliate		(274)
Net cash used in investing activities	(69,191)	(12,997)
Financing activities:
Debt issuance cost	(5,668)	0
Proceeds from line of credit		34,295
Payments on line of credit		(29,575)
Repurchase of common stock		(51)
Proceeds from Term Loan	70,000	0
Net cash provided by financing activities	64,332	4,669
Effect of exchange rate changes on cash	(483)	0
Decrease in cash, cash equivalents and restricted cash	(29,019)	(2,918)
Cash, cash equivalents and restricted cash at the beginning of period	58,564	8,770
Cash, cash equivalents and restricted cash at end of period	29,545	5,852
Cash paid during the period for:
Reorganization items, net	6,204	0
Interest	3,599	15,755
Income taxes	1,688	813
Noncash investing activities:
Other current liabilities and accrued payables related to purchase of property and equipment	$ 96	$ 272