Unaudited Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 16,557	$ 2,871
Adjustments to reconcile net income to net cash provided by (used in) operations:
Depreciation and amortization	18,357	15,170
Amortization of stock-based compensation	1,640	1,689
Amortization of deferred financing costs	463	372
Provision for doubtful accounts receivable, net of write-offs	(226)	(442)
Deferred income tax provision	(245)	112
Foreign currency transaction gain	(242)	(598)
Change in operating assets and liabilities:
Accounts receivable	(2,699)	(9,499)
Prepaids and other	(3,044)	(1,300)
Accounts payable	(2,756)	(4,354)
Other accrued liabilities and other	(10,156)	(10,178)
Net cash provided by (used in) operating activities	17,649	(6,157)
Cash flows from investing activities:
Purchases of vessels, equipment and other fixed assets	(96,117)	(45,908)
Release of deposits held in escrow		7,945
Proceeds from disposition of vessels and equipment		638
Net cash used in investing activities	(96,117)	(37,325)
Cash flows from financing activities:
Proceeds from borrowings under revolving loan facility	50,045
Cash dividends	(6,824)	(6,604)
Stock repurchases		(12,389)
Debt issuance costs		(1,579)
Proceeds from issuance of stock	288	234
Net cash provided by (used in) financing activities	43,509	(20,338)
Effect of exchange rate changes on cash	98	(2,267)
Net decrease in cash and cash equivalents	(34,861)	(66,087)
Cash and cash equivalents at beginning of the period	60,566	185,175
Cash and cash equivalents at end of period	25,705	119,088
Supplemental cash flow information:
Interest paid, net of interest capitalized	14,407	13,858
Income taxes paid, net	$ 859	$ 977