Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income (loss)	$ (38,494)	$ 17,007
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	57,239	53,528
Amortization of debt issuance costs	5,138	2,596
Share-based compensation	2,867	3,515
Amortization of debt discount	3,134	2,928
Deferred income taxes	(10,047)	(2,454)
Excess tax benefit from share-based compensation	0	(86)
Equity in losses of investments	244	0
Gain on repurchase of long-term debt	(302)	0
Unrealized (gain) loss and ineffectiveness on derivative contracts, net	(6,147)	1,941
Changes in operating assets and liabilities:
Accounts receivable, net	19,062	(29,006)
Other current assets	(3,055)	11,904
Income tax receivable, net of income tax payable	8,843	(9,472)
Accounts payable and accrued liabilities	(7,979)	(35,318)
Other noncurrent, net	(5,614)	(14,050)
Net cash provided by operating activities	24,889	3,033
Cash flows from investing activities:
Capital expenditures	(57,563)	(232,872)
Distributions from equity investments, net of earnings	1,200	3,842
Proceeds from sale of equity investment	25,000	0
Proceeds from sale of assets	10,887	7,500
Net cash used in investing activities	(20,476)	(221,530)
Cash flows from financing activities:
Proceeds from Nordea Q5000 Loan	0	250,000
Repayment of Nordea Q5000 Loan	(17,858)	0
Repayment of Term Loan	(15,000)	(7,500)
Repayment of MARAD Debt	(2,927)	(2,788)
Repurchase of Convertible Senior Notes due 2032	(6,480)	0
Debt issuance costs	(1,230)	(1,533)
Net proceeds from issuance of common stock	38,773	0
Repurchase of common stock	(187)	(1,056)
Excess tax benefit from share-based compensation	0	86
Proceeds from issuance of ESPP shares	600	2,512
Net cash provided by (used in) financing activities	(4,309)	239,721
Effect of exchange rate changes on cash and cash equivalents	(2,106)	2,346
Net increase (decrease) in cash and cash equivalents	(2,002)	23,570
Cash and cash equivalents:
Balance, beginning of year	494,192	476,492
Balance, end of period	$ 492,190	$ 500,062