Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ (27,823)	$ 19,642
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	31,565	26,089
Amortization of debt issuance costs	3,837	1,218
Stock-based compensation expense	1,408	1,754
Amortization of debt discount	1,567	1,464
Deferred income taxes	(8,931)	(1,114)
Excess tax benefit from stock-based compensation	0	(260)
Equity in losses of investments	123	0
Unrealized (gain) loss and ineffectiveness on derivative contracts, net	(4,349)	2,181
Changes in operating assets and liabilities:
Accounts receivable, net	31,522	(14,917)
Other current assets	(2,505)	10,343
Income tax payable	(2,815)	(5,322)
Accounts payable and accrued liabilities	(21,108)	(48,718)
Other noncurrent, net	(1,684)	(2,403)
Net cash provided by (used in) operating activities	807	(10,043)
Cash flows from investing activities:
Capital expenditures	(22,869)	(52,524)
Distributions from equity investments, net of earnings	1,200	1,379
Proceeds from sale of equity investment	25,000	0
Proceeds from sale of assets	10,887	7,500
Net cash used in investing activities	14,218	(43,645)
Cash flows from financing activities:
Repayment of Nordea Q5000 Loan	(8,929)	0
Repayment of Term Loan	(7,500)	(3,750)
Repayment of MARAD Debt	(2,927)	(2,788)
Debt issuance costs	(1,211)	0
Repurchases of common stock	(173)	(1,026)
Excess tax benefit from stock-based compensation	0	260
Proceeds from issuance of ESPP shares	600	1,299
Net cash used in financing activities	(20,140)	(6,005)
Effect of exchange rate changes on cash and cash equivalents	(893)	(1,497)
Net decrease in cash and cash equivalents	(6,008)	(61,190)
Cash and cash equivalents:
Balance, beginning of year	494,192	476,492
Balance, end of period	$ 488,184	$ 415,302