Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ 1,318	$ (2,560)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	28,509	27,782
Amortization of debt discounts	1,513	1,360
Amortization of debt issuance costs	902	935
Share-based compensation	2,719	2,500
Deferred income taxes	(10)	108
Equity in losses of investment	40	136
Loss on extinguishment of long-term debt	0	1,105
Unrealized gain on derivative contracts, net	(829)	(1,534)
Changes in operating assets and liabilities:
Accounts receivable, net	(22,584)	22,761
Other current assets	(13,129)	(3,948)
Income tax payable	(2,370)	(2,853)
Accounts payable and accrued liabilities	(17,027)	(12,256)
Other, net	13,298	(7,510)
Net cash provided by (used in) operating activities	(34,246)	41,046
Cash flows from investing activities:
Capital expenditures	(11,655)	(21,214)
Proceeds from sale of assets	25	0
Other	(326)	0
Net cash used in investing activities	(11,956)	(21,214)
Cash flows from financing activities:
Issuance of Convertible Senior Notes due 2023	0	125,000
Repurchase of Convertible Senior Notes due 2032	0	(59,478)
Repayment of Term Loan	(936)	(61,468)
Repayment of Nordea Q5000 Loan	(8,929)	(8,929)
Repayment of MARAD Debt	(3,387)	(3,226)
Debt issuance costs	(113)	(3,774)
Payments related to tax withholding for share-based compensation	(826)	(1,058)
Proceeds from issuance of ESPP shares	136	159
Net cash used in financing activities	(14,055)	(12,774)
Effect of exchange rate changes on cash and cash equivalents	821	335
Net increase (decrease) in cash and cash equivalents	(59,436)	7,393
Cash and cash equivalents:
Balance, beginning of year	279,459	266,592
Balance, end of period	$ 220,023	$ 273,985