2.2.0.7 false Share-Based Compensation (Details) (USD $) 40701 - Disclosure - Share-Based Compensation (Details) true false false false 1 USD false false Unit12 Standard http://www.xbrl.org/2003/instance pure xbrli 0 Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ 2 Share-Based Compensation 0 us-gaap_ShareBasedCompensationAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 3 Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 1 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false true false false 560354 560354 false false false xbrli:sharesItemType shares The number of shares issuable under a share-based award plan pertaining to grants made during the period on other than stock option plans (for example, phantom stock plan, stock appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(c) false 4 Rate non-vested share awards generally vest 1 esv_RateNonVestedShareAwardsGenerallyVest esv false na duration Rate non-vested share awards generally vest false false false false false false false false false false false label false 1 false true false false 0.2 0.2 false false false us-types:percentItemType pure Rate non-vested share awards generally vest No authoritative reference available. false 5 Non-vested share awards granted to certain officers vest rate 1 esv_NonVestedShareAwardsGrantedToCertainOfficersVestRate esv false na duration Non-vested share awards granted to certain officers vest rate false false false false false false false false false false false label false 1 false true false false 0.33 0.33 false false false us-types:percentItemType pure Non-vested share awards granted to certain officers vest rate No authoritative reference available. false 6 Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value 1 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue us-gaap true na duration No definition available. false false false false false false false false false false false true 1 true true false false 35.11 35.11 false false false us-types:perShareItemType decimal The weighted average fair value at grant for nonvested share-based awards issued during the period on other than stock option plans (for example, phantom stock plan, stock appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(c) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph c(1) false 7 Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period 1 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false true false false 160293 160293 false false false xbrli:sharesItemType shares The quantity of shares issuable on stock options awarded under the plan during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(d) false 8 Weighted-average grant-date fair value 1 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue us-gaap true na duration No definition available. false false false false false false false false false false false terselabel true 1 true true false false 11.05 11.05 false false false us-types:perShareItemType decimal The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph c(1) false 9 Weighted-average exercise price 1 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false false false false terselabel true 1 true true false false 34.45 34.45 false false false us-types:perShareItemType decimal The weighted average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on stock options awarded under the plan during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(d) false 10 Risk-free interest rate 1 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 0.018 0.018 false false false us-types:percentItemType pure The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(d) false 11 Expected life (in years) 1 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 4.01 4.01 false false false xbrli:decimalItemType decimal The period of time a share-based award is expected to be outstanding. A share-based award's expected term shall be determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior. An entity is required to aggregate individual awards into relatively homogeneous groups. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section D -Subsection 2 false 12 Expected volatility 1 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 0.531 0.531 false false false us-types:percentItemType pure An entity using a valuation technique with different volatilities during the contractual term must disclose the range of expected volatilities used and the weighted-average expected volatility. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(b) false 13 Dividend yield on share options granted during the period 1 esv_DividendYieldOnShareOptionsGrantedDuringPeriod esv false na duration Dividend yield on share options granted during the period false false false false false false false false false false false terselabel false 1 false true false false 0.041 0.041 false false false us-types:percentItemType pure Dividend yield on share options granted during the period No authoritative reference available. false 14 Share options granted, increments exercisable annually 1 esv_ShareOptionsGrantedIncrementsExercisableAnnually esv false na duration Share options granted, increments exercisable annually false false false false false false false false false false false terselabel false 1 false true false false 0.33 0.33 false false false us-types:percentItemType pure Share options granted, increments exercisable annually No authoritative reference available. false 15 Share options granted, exercisable period in years 1 esv_ShareOptionsGrantedExercisablePeriodInYears esv false na duration Share options granted, exercisable period in years false false false false false false false false false false false terselabel false 1 false true false false 3 3 false false false xbrli:positiveIntegerItemType positiveinteger Share options granted, exercisable period in years No authoritative reference available. false 16 Share options granted, expiration in years 1 esv_ShareOptionsGrantedExpirationInYears esv false na duration Share options granted, expiration in years false false false false false false false false false false false terselabel false 1 false true false false 7 7 false false false xbrli:positiveIntegerItemType positiveinteger Share options granted, expiration in years No authoritative reference available. false 1 15 false UnKnown NoRounding NoRounding true true