XML 59 R59.htm IDEA: XBRL DOCUMENT v2.4.1.9

Fair Value Measurements (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Apr. 30, 2015
Canadian Operations
Fair value measurement of assets and liabilities
Settlement amount for outstanding note receivable			$ 5.1exh_LongTermReceivableFromSaleOfDiscontinuedOperationsSettlementAmount / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = exh_CanadaOperationsMember
Impaired long-lived assets
Fair value measurement of assets and liabilities
Weighted average disposal period of impaired assets	4 years	4 years
Discount rate (as a percent)	10.00%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = exh_ImpairedLongLivedAssetsMember	9.00%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = exh_ImpairedLongLivedAssetsMember

X

- Definition

Weighted average disposal period used to find the present value of an amount to be paid or received in the future as an input to measure fair value.

+ References

No definition available.

+ Details

Name:	exh_FairValueInputsWeightedAverageDisposalPeriod
Namespace Prefix:	exh_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the settlement amount of long-term receivable from sale of discontinued operations.

+ References

No definition available.

+ Details

Name:	exh_LongTermReceivableFromSaleOfDiscontinuedOperationsSettlementAmount
Namespace Prefix:	exh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

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

X

- 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=36462937&loc=d3e19207-110258

+ Details

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

X

- Details

Name:	us-gaap_FairValueByAssetClassAxis=exh_ImpairedLongLivedAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=exh_CanadaOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: