Note 4 - Income Taxes (Details Textual) - USD ($)	6 Months Ended
Dec. 31, 2015	Jun. 30, 2015
Scenario, Forecast [Member]
Foreign Earnings Repatriated	$ 0
Incremental US Tax if Earnings were Repatriated, Percent		30.00%

Incremental U.S tax in percentage if the unremitted earnings of non-U.S. subsidiaries were repatriated.

No definition available.

Name:	glf_IncrementalUSTaxIfEarningsWereRepatriatedPercent
Namespace Prefix:	glf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration