Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Condensed Consolidated Statements of Operations [Abstract]
Revenue	$ 103,778	$ 94,479	$ 281,978	$ 271,912
Costs and expenses:
Direct operating expenses	48,103	41,729	139,328	127,456
Drydock expense	5,726	7,242	15,933	20,365
General and administrative expenses	11,859	10,236	34,192	33,423
Depreciation and amortization	14,896	14,492	44,554	42,444
(Gain) loss on sale of assets		(5,201)	10	(5,095)
Impairment charge				97,665
Total costs and expenses	80,584	68,498	234,017	316,258
Operating income (loss)	23,194	25,981	47,961	(44,346)
Other income (expense):
Interest expense	(5,757)	(5,807)	(17,114)	(15,858)
Interest income	195	597	379	739
Foreign currency gain (loss) and other	(2,803)	(603)	(2,786)	158
Total other expense	(8,365)	(5,813)	(19,521)	(14,961)
Income (loss) before income taxes	14,829	20,168	28,440	(59,307)
Income tax (provision) benefit	(664)	(961)	(2,151)	9,326
Net income (loss)	$ 14,165	$ 19,207	$ 26,289	$ (49,981)
Earnings (loss) per share:
Basic	$ 0.54	$ 0.74	$ 1.01	$ (1.96)
Diluted	$ 0.54	$ 0.73	$ 1.00	$ (1.96)
Weighted average shares outstanding:
Basic	25,869	25,599	25,793	25,512
Diluted	25,989	25,737	25,922	25,512