FAIR VALUE AND DERIVATIVE INSTRUMENTS (Details 2) (Recurring, Acquired intangible assets, Discounted cash flow, Level 3)	6 Months Ended
Jun. 30, 2013
Unobservable inputs
Long term growth rate (as a percent)	3.00%
Minimum
Unobservable inputs
Discount rate (as a percent)	19.00%
Royalty rate (as a percent)	2.00%
Maximum
Unobservable inputs
Discount rate (as a percent)	20.00%
Royalty rate (as a percent)	3.00%

Represents the percentage of assumed royalty in revenues, used as an input to measure fair value.

No definition available.

Name:	hdng_FairValueInputsRoyaltyRate
Namespace Prefix:	hdng_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FairValueInputsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of assumed long-term growth in revenues, used as an input to measure fair value.

+ References

+ Details

Name:	us-gaap_FairValueInputsLongTermRevenueGrowthRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration