Related Party Transactions (Details Textual) (Sagard [Member])	1 Months Ended
Jan. 31, 2012
Sagard [Member]
Common Stock Privately Purchased	350,000

Represents the number of common stock privately purchased.

No definition available.

Name:	gpx_CommonStockPrivatelyPurchased
Namespace Prefix:	gpx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration