Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net loss	$ (22,818)	$ (38,494)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	56,377	57,239
Amortization of debt discount	2,303	3,134
Amortization of debt issuance costs	4,326	5,138
Share-based compensation	5,181	2,867
Deferred income taxes	(80)	(10,047)
Equity in losses of investment	304	244
Loss on disposition of assets, net	39	0
(Gain) loss on early extinguishment of long-term debt	397	(302)
Unrealized gain and ineffectiveness on derivative contracts, net	(2,482)	(6,147)
Changes in operating assets and liabilities:
Accounts receivable, net	(10,122)	19,062
Other current assets	(10,957)	(3,055)
Income tax receivable	(1,729)	8,843
Accounts payable and accrued liabilities	27,372	(7,979)
Other non-current, net	(32,510)	(5,614)
Net cash provided by operating activities	15,601	24,889
Cash flows from investing activities:
Capital expenditures	(94,396)	(57,563)
Distribution from equity investment	0	1,200
Proceeds from sale of equity investment	0	25,000
Proceeds from sale of assets	10,000	10,887
Net cash used in investing activities	(84,396)	(20,476)
Cash flows from financing activities:
Proceeds from term loan	100,000	0
Repayment of term loan	(192,258)	(15,000)
Repayment of Nordea Q5000 Loan	(17,858)	(17,858)
Repayment of MARAD Debt	(3,073)	(2,927)
Repurchase of Convertible Senior Notes due 2032	0	(6,480)
Debt issuance costs	(3,665)	(1,230)
Net proceeds from issuance of common stock	219,504	38,773
Payments related to tax withholding for share-based compensation	(1,306)	(187)
Proceeds from issuance of ESPP shares	279	600
Net cash provided by (used in) financing activities	101,623	(4,309)
Effect of exchange rate changes on cash and cash equivalents	960	(2,106)
Net increase (decrease) in cash and cash equivalents	33,788	(2,002)
Cash and cash equivalents:
Balance, beginning of year	356,647	494,192
Balance, end of period	$ 390,435	$ 492,190