v2.4.0.8

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) | 9 Months Ended | 3 Months Ended | 1 Months Ended | 9 Months Ended | 1 Months Ended | 9 Months Ended
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2014 Person | Sep. 30, 2014 Non-employee director option plan | Jun. 30, 2014 Revisions of Prior Period Reported Amounts | Jun. 30, 2014 Revisions of Prior Period Reported Amounts Treasury Stock | Jun. 30, 2014 Revisions of Prior Period Reported Amounts Additional Paid-in Capital | May 31, 2012 Performance Stock Units | Sep. 30, 2014 Performance Stock Units | Sep. 30, 2013 Performance Stock Units | Apr. 30, 2013 Market-performance based restricted stock units (MSUs) | Apr. 30, 2014 Performance Shares Share-based Compensation Award, Tranche One | Apr. 30, 2014 Performance Shares Share-based Compensation Award, Tranche Two | Sep. 30, 2014 Performance Shares Non-employee director option plan | Sep. 30, 2014 Restricted stock units | Sep. 30, 2013 Restricted stock units | Sep. 30, 2014 Restricted stock units Non-employee director option plan
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum number of customers, partners and employees using BIRT | 200,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum number of developers uses BIRT | 3,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revisions of prior period reported amounts |  |  |  | $ 3,750,000 | $ (3,470,000) |  |  |  |  |  |  |  |  |  |
Revisions of prior period reported amounts, effect on retained earning |  |  | (280,000) |  |  |  |  |  |  |  |  |  |  |  |
Award vesting period |  | 4 years |  |  |  | 2 years |  |  |  | 3 years | 2 years |  | 4 years |  |
Percentage of stock units granted |  |  |  |  |  | 200.00% |  |  | 200.00% | 100.00% | 150.00% |  |  |  |
Percentage of earned award vested |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |  |
Remaining percentage of earned award to be vested |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |  |
Expected dividend yield in the option valuation model | $ 0 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share reserve ratio |  |  |  |  |  |  |  |  |  |  |  |  | 1 |  |
Share-based awards granted |  |  |  |  |  |  | 325,000 | 125,000 |  |  |  | 685,000 | 1,262,500 | 447,500 | 2,348,750
Tax benefit realized upon settlement | Greater than 50% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Period of significant increase decrease in unrecognized tax benefits | 12 months |  |  |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition Description of percentage of realization of tax benefit upon settlement. + References No definition available. + Details
Name: | birt_DescriptionOfPercentageOfRealizationOfTaxBenefitUponSettlement
Namespace Prefix: | birt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Developers + References No definition available. + Details
Name: | birt_NumberOfDevelopers
Namespace Prefix: | birt_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Users + References No definition available. + Details
Name: | birt_NumberOfUsers
Namespace Prefix: | birt_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period Of Significant Increase Decrease In Unrecognized Tax Benefits + References No definition available. + Details
Name: | birt_PeriodOfSignificantIncreaseDecreaseInUnrecognizedTaxBenefits
Namespace Prefix: | birt_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share based compensation arrangement by share based payment award award vesting percentage after initial performance period. + References No definition available. + Details
Name: | birt_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPercentageAfterInitialPerformancePeriod
Namespace Prefix: | birt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share based compensation arrangement by share based payment award award vesting percentage after one year service period. + References No definition available. + Details
Name: | birt_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPercentageAfterOneYearServicePeriod
Namespace Prefix: | birt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share Reserve Ratio + References No definition available. + Details
Name: | birt_ShareReserveRatio
Namespace Prefix: | birt_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | birt_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix: | birt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of the cumulative effect on retained earnings net of related income tax effect. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=28359718&loc=d3e22663-107794 + Details
Name: | us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of a reclassification adjustment made to prior period financial statement amounts. + References No definition available. + Details
Name: | us-gaap_PriorPeriodReclassificationAdjustment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of vesting of share-based compensation awards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of the weighted average expected dividend for an entity using a valuation technique with different dividend rates during the contractual term. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageExpectedDividend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration