Unaudited Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net loss	$ (163,491,000)	$ (198,597,000)
Adjustments to reconcile net loss to net cash provided by operations:
Depreciation and amortization	44,785,000	55,927,000
Amortization of stock-based compensation	4,023,000	5,270,000
Amortization of deferred financing costs	2,675,000	1,799,000
Provision for doubtful accounts receivable, net of write-offs	1,155,000	(960,000)
Impairment charges	162,808,000	152,103,000
(Gain) loss on sale of assets	5,982,000	(784,000)
Gain on extinguishment of debt	(35,912,000)
Deferred income tax provision (benefit)	(44,508,000)	2,689,000
Foreign currency transaction loss	3,077,000	157,000
Change in operating assets and liabilities:
Accounts receivable	16,724,000	33,281,000
Prepaids and other	725,000	(2,674,000)
Accounts payable	(1,053,000)	(6,998,000)
Other accrued liabilities and other	(15,376,000)	(15,924,000)
Net cash (used in) provided by operating activities	(18,386,000)	25,289,000
Cash flows from investing activities:
Purchases of vessels, equipment and other fixed assets	(15,076,000)	(31,874,000)
Release of deposits held in escrow		3,683,000
Proceeds from disposition of vessels and equipment	5,029,000	8,226,000
Net cash used in investing activities	(10,047,000)	(19,965,000)
Cash flows from financing activities:
Proceeds from borrowings under revolving loan facilities	55,194,000	39,000,000
Repayment of borrowings under revolving loan facilities	(5,000,000)	(60,000,000)
Repurchase of Senior Notes	(33,448,000)
Debt issuance costs	(831,000)	(2,578,000)
Proceeds from issuance of stock	305,000	702,000
Net cash provided by (used in) financing activities	16,220,000	(22,876,000)
Effect of exchange rate changes on cash	53,000	(2,061,000)
Net decrease in cash and cash equivalents	(12,160,000)	(19,613,000)
Cash and cash equivalents at beginning of period	21,939,000	50,785,000
Cash and cash equivalents at end of period	9,779,000	31,172,000
Supplemental cash flow information:
Interest paid, net of interest capitalized	30,206,000	30,169,000
Income taxes paid, net	$ 2,291,000	$ 1,371,000