Note 8 - Operating Income (Loss) by Operating Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Quarter Ended March 31, 2015
Revenue	$ 89,092us-gaap_MarineServicesRevenue	$ 119,600us-gaap_MarineServicesRevenue
Direct operating expenses	51,225us-gaap_DirectOperatingCosts	56,299us-gaap_DirectOperatingCosts
Drydock expense	8,973glf_DryDockexpense	7,211glf_DryDockexpense
General and administrative	10,964us-gaap_GeneralAndAdministrativeExpense	14,489us-gaap_GeneralAndAdministrativeExpense
Depreciation expense	18,488us-gaap_Depreciation	18,357us-gaap_Depreciation
Operating income (loss)	(558)us-gaap_OperatingIncomeLoss	23,244us-gaap_OperatingIncomeLoss
Americas [Member]
Quarter Ended March 31, 2015
Revenue	35,563	48,673
Direct operating expenses	22,877	24,086
Drydock expense	5,381	2,990
General and administrative	2,756	3,117
Depreciation expense	7,846	6,806
Operating income (loss)	(3,297)	11,674
North Sea [Member]
Quarter Ended March 31, 2015
Revenue	40,200	52,623
Direct operating expenses	24,165	26,729
Drydock expense	2,933	2,668
General and administrative	2,062	3,492
Depreciation expense	7,222	7,823
Operating income (loss)	3,818	11,911
Other1 [Member]
Quarter Ended March 31, 2015
General and administrative	5,023	6,518
Depreciation expense	826	832
Operating income (loss)	(5,849)	(7,350)
South East Asia [Member]
Quarter Ended March 31, 2015
Revenue	13,329	18,304
Direct operating expenses	4,183	5,484
Drydock expense	659	1,553
General and administrative	1,123	1,362
Depreciation expense	2,594	2,896
Operating income (loss)	$ 4,770	$ 7,009

Expense related to construction,maintenance and repair of ships,boats and other water crafts.

No definition available.

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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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- Definition

The aggregate direct operating costs incurred during the reporting period.

+ References

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- Definition

The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

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- Definition

Revenue from marine-related services and products such as lubricants for offshore drilling, and retail or wholesale sales in a marina.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 23

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62136-109447

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62246-109447

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- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

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