XML 67 R83.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Long-Term Debt (Details 7) (USD $) | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Jun. 30, 2014 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Jun. 30, 2009
Long-Term Debt |  |  |  |  |
Amortization of debt discount |  | $ 12,380,000 us-gaap_AmortizationOfDebtDiscountPremium | $ 23,407,000 us-gaap_AmortizationOfDebtDiscountPremium | $ 20,523,000 us-gaap_AmortizationOfDebtDiscountPremium |
Value of shares acquired upon exercise of call options |  | 89,407,000 exh_ValueOfSharesAcquiredUponExerciseOfCallOptions |  |  |
4.25% convertible senior notes due June 2014 |  |  |  |  |
Long-Term Debt |  |  |  |  |
Principle amount of senior notes |  |  |  |  | 355,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member
Interest rate (as a percent) |  | 4.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member | 4.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  | 4.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member
Conversion rate of debt instrument (Shares per USD) | 0.0435084 us-gaap_DebtInstrumentConvertibleConversionRatio1 / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |  |
Conversion price per common stock shares (in dollars per share) | $ 22.98 us-gaap_DebtInstrumentConvertibleConversionPrice1 / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |  |
Repayment of long term debt | 370,000,000 us-gaap_RepaymentsOfConvertibleDebt / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |  |
Number of shares of common stock issued upon redemption of debt | 6,800,000 us-gaap_DebtConversionConvertedInstrumentSharesIssued1 / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |  |
Amount of unamortized discount of notes |  |  | 11,300,000 us-gaap_DebtInstrumentUnamortizedDiscount / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  | 97,900,000 us-gaap_DebtInstrumentUnamortizedDiscount / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member
Recognized interest expense related to the contractual interest coupon |  | 6,900,000 us-gaap_InterestExpenseDebt / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member | 15,100,000 us-gaap_InterestExpenseDebt / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member | 15,100,000 us-gaap_InterestExpenseDebt / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |
Amortization of debt discount |  | 11,300,000 us-gaap_AmortizationOfDebtDiscountPremium / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member | 23,000,000 us-gaap_AmortizationOfDebtDiscountPremium / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member | 20,500,000 us-gaap_AmortizationOfDebtDiscountPremium / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |
Effective interest rate (as a percent) |  |  |  |  | 11.67%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member
Price per share of common stock for call options purchased (in dollars per share) | $ 22.98 exh_CallOptionsPricePerShare / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |  |
Warrant exercise price (in dollars per share) |  | $ 32.19 us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1 / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |
Effective conversion price (in dollars per share) |  | $ 32.19 exh_DebtInstrumentEffectiveConversionPrice / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |
Debt instrument face amount for effective conversion price |  | 325,000,000 exh_DebtInstrumentFaceAmountForEffectiveConversionPrice / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |
Number of shares acquired upon exercise of call options | 6,500,000 exh_AdjustmentsToEquitySharesAcquiredFromExerciseOfCallOptionsShares / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |  |
Value of shares acquired upon exercise of call options | $ 89,400,000 exh_ValueOfSharesAcquiredUponExerciseOfCallOptions / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |  |
Trading days within which counterparties have the right to exercise warrants |  | 80 days |  |  |
Common shares issued pursuant to warrants exercised |  | 1,600,000 exh_AdjustmentsToEquityStockIssuedDuringPeriodSharesWarrantsExercised / us-gaap_LongtermDebtTypeAxis = exh_ConvertibleSeniorNotesDueJune2014Member |  |  |

X
- Definition Number of shares related to shares acquired from exercise of call options. + References No definition available. + Details
Name: | exh_AdjustmentsToEquitySharesAcquiredFromExerciseOfCallOptionsShares
Namespace Prefix: | exh_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares related to stock issued as a result of the exercise of warrants. + References No definition available. + Details
Name: | exh_AdjustmentsToEquityStockIssuedDuringPeriodSharesWarrantsExercised
Namespace Prefix: | exh_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Price per share of common stock for call options purchased. + References No definition available. + Details
Name: | exh_CallOptionsPricePerShare
Namespace Prefix: | exh_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Period of specified consecutive trading days within which counterparties have the right to exercise warrants, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | exh_ClassOfWarrantOrRightExercisePeriod
Namespace Prefix: | exh_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The effective conversion price per share. + References No definition available. + Details
Name: | exh_DebtInstrumentEffectiveConversionPrice
Namespace Prefix: | exh_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the face amount of senior notes used for effective conversion price. + References No definition available. + Details
Name: | exh_DebtInstrumentFaceAmountForEffectiveConversionPrice
Namespace Prefix: | exh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the value of shares acquired upon exercise of call options. + References No definition available. + Details
Name: | exh_ValueOfSharesAcquiredUponExerciseOfCallOptions
Namespace Prefix: | exh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 + Details
Name: | us-gaap_AmortizationOfDebtDiscountPremium
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(4)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 + Details
Name: | us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The price per share of the conversion feature embedded in the debt instrument. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870 + Details
Name: | us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(5)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Conversion Rate -URI http://asc.fasb.org/extlink&oid=6509012 + Details
Name: | us-gaap_DebtInstrumentConvertibleConversionRatio1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of the cost of borrowed funds accounted for as interest expense for debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 + Details
Name: | us-gaap_InterestExpenseDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash outflow from the repayment of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 + Details
Name: | us-gaap_RepaymentsOfConvertibleDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=exh_ConvertibleSeniorNotesDueJune2014Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |