Fair Value of Financial Instruments (Details Textual) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Fair Value of Financial Instruments (Textual) [Abstract]
Assets or liabilities measured at fair value on a nonrecurring basis	$ 0	$ 0

Assets or liabilities fair value disclosure nonrecurring.

No definition available.

Name:	grh_AssetsOrLiabilitiesFairValueDisclosureNonrecurring
Namespace Prefix:	grh_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant