Subsequent Events (Details) - vessel	Mar. 31, 2019	Dec. 31, 2018
Subsequent Events [Abstract]
Number of multi-purpose service vessels	2	2

Construction In Progress, Number Of Multi-Purpose Service Vessels

No definition available.

Name:	gifi_ConstructionInProgressNumberOfMultiPurposeServiceVessels
Namespace Prefix:	gifi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant