Organization and Business (Details)	12 Months Ended
Dec. 31, 2018 Investment
Organization and Business [Abstract]
Other series owned by entity	1

Number of other investment series owned by the entity during the period.

No definition available.

Name:	gaifb_OtherSeriesOwnedByEntity
Namespace Prefix:	gaifb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration