Unaudited Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 119,088	$ 185,175
Trade accounts receivable, net of allowance for doubtful accounts of $2,607 and $3,250, respectively	92,319	85,706
Other accounts receivable	9,337	8,506
Prepaid expenses and other current assets	26,867	25,186
Total current assets	247,611	304,573
Vessels, equipment, and other fixed assets at cost, net of accumulated depreciation of $389,830 and $389,469, respectively	1,104,674	1,136,360
Construction in progress	202,509	169,429
Goodwill	31,824	33,438
Intangibles, net of accumulated amortization of $13,696 and $12,975, respectively	20,903	21,624
Cash held in escrow	39,099	47,028
Deferred costs and other assets	32,562	33,222
Total assets	1,679,182	1,745,674
Current liabilities:
Accounts payable	23,936	29,089
Income and other taxes payable	4,698	6,262
Accrued personnel costs	21,564	23,656
Accrued interest expense	1,481	9,327
Other accrued liabilities	11,657	11,402
Total current liabilities	63,336	79,736
Long-term debt	500,969	500,999
Long-term income taxes:
Deferred tax liabilities	105,862	105,867
Other income taxes payable	22,175	23,665
Other liabilities	8,059	7,525
Stockholders' equity:
Class A Common Stock, $0.01 par value; 60,000 shares authorized; 27,064 and 26,941 shares issued and 26,699 and 26,906 outstanding, respectively; Class B Common Stock $0.01 per value; 60,000 shares authorized; no shares issued	268	266
Additional paid-in capital	391,849	389,881
Retained earnings	575,371	579,062
Accumulated other comprehensive income	24,246	59,875
Treasury stock, at cost	(23,453)	(11,533)
Deferred compensation expense	10,500	10,331
Total stockholders' equity	978,781	1,027,882
Total liabilities and stockholders' equity	$ 1,679,182	$ 1,745,674