Unaudited Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income	$ 30,756	$ 12,727
Adjustments to reconcile net income to net cash provided by operations:
Depreciation and amortization	37,561	30,195
Loss on sale of assets		126
Amortization of stock-based compensation	3,790	5,796
Amortization of deferred financing costs	926	819
Provision for doubtful accounts receivable, net of write-offs	2,174	(425)
Impairment charge	7,459
Deferred income tax provision	138	380
Foreign currency transaction gain	(932)	(146)
Change in operating assets and liabilities:
Accounts receivable	(28,440)	(33,689)
Prepaids and other	(3,048)	1,603
Accounts payable	1,053	(4,351)
Other accrued liabilities and other	(1,956)	(824)
Net cash provided by operating activities	49,481	12,211
Cash flows from investing activities:
Purchases of vessels, equipment and other fixed assets	(121,631)	(110,968)
Release of deposits held in escrow	5,060	14,771
Proceeds from disposition of vessels and equipment		648
Net cash used in investing activities	(116,571)	(95,549)
Cash flows from financing activities:
Proceeds from borrowings under revolving loan facility	50,045
Repayment of secured credit facilities	(5,000)
Cash dividends	(13,421)	(13,345)
Stock repurchases		(12,389)
Debt issuance costs		(1,579)
Proceeds from issuance of stock	522	683
Net cash (used in) provided by financing activities	32,146	(26,630)
Effect of exchange rate changes on cash	318	(2,506)
Net increase (decrease) in cash and cash equivalents	(34,626)	(112,474)
Cash and cash equivalents at beginning of the period	60,566	185,175
Cash and cash equivalents at end of period	25,940	72,701
Supplemental cash flow information:
Interest paid, net of interest capitalized	12,387	10,272
Income taxes paid, net	$ 2,362	$ 2,467