XML 58 R44.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Summary of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Sep. 30, 2014 | Sep. 30, 2013
Asset Retirement Obligation | $ 3.2 | $ 3.6
Exposure to Workers Compensation Claims, Per Incident | 1 |
Workers Compensation Undiscounted Basis Liability | 17.0 | 20.0
Workers' Compensation Liability | 14.7 | 17.2
Income Tax Benefit, Likelihood of Realization Threshold | 50.00% |
Deferred Finance Costs, Net | 6.7 |
Minimum [Member] |  |
Finite-Lived Tangible Asset, Useful Life, Maximum | 3 years |
Debt Instrument, Term | 5 years |
Maximum [Member] |  |
Finite-Lived Tangible Asset, Useful Life, Maximum | 10 years |
Debt Instrument, Term | 10 years |
Land Improvements [Member] | Minimum [Member] |  |
Property, Plant and Equipment, Useful Life, Minimum | 10 years |
Land Improvements [Member] | Maximum [Member] |  |
Property, Plant and Equipment, Useful Life, Minimum | 20 years |
Building [Member] | Minimum [Member] |  |
Property, Plant and Equipment, Useful Life, Minimum | 10 years |
Building [Member] | Maximum [Member] |  |
Property, Plant and Equipment, Useful Life, Minimum | 40 years |
Machinery and Equipment [Member] | Minimum [Member] |  |
Property, Plant and Equipment, Useful Life, Minimum | 3 years |
Machinery and Equipment [Member] | Maximum [Member] |  |
Property, Plant and Equipment, Useful Life, Minimum | 15 years |
Software and Software Development Costs [Member] | Minimum [Member] |  |
Property, Plant and Equipment, Useful Life, Minimum | 3 years |
Software and Software Development Costs [Member] | Maximum [Member] |  |
Property, Plant and Equipment, Useful Life, Minimum | 6 years |
U.S. Pipe [Member] | Maximum [Member] |  |
Discontinued Operations, Receivable from Buyer of Discontinued Operation | 6.5 | 11.8
Other Current Assets [Member] | U.S. Pipe [Member] |  |
Discontinued Operations, Receivable from Buyer of Discontinued Operation | 1.6 |
Other Noncurrent Assets [Member] | U.S. Pipe [Member] |  |
Discontinued Operations, Receivable from Buyer of Discontinued Operation | 4.0 |
ABL Agreement [Member] |  |
Deferred Finance Costs, Net | 2.1 |
Seven Point Three Seven Five Senior Subordinated Notes [Member] |  |
Deferred Finance Costs, Net | 2.8 |
Eight Point Seven Five Senior Unsecured Notes [Member] |  |
Deferred Finance Costs, Net | $ 1.8 |

X
- Definition Discontinued Operations, Receivable from Buyer of Discontinued Operation + References No definition available. + Details
Name: | mwa_DiscontinuedOperationsReceivableFromBuyerOfDiscontinuedOperation
Namespace Prefix: | mwa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Exposure to Workers Compensation Claims, Per Incident + References No definition available. + Details
Name: | mwa_ExposureToWorkersCompensationClaimsPerIncident
Namespace Prefix: | mwa_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Finite-Lived Tangible Asset Useful Life + References No definition available. + Details
Name: | mwa_FiniteLivedTangibleAssetUsefulLife
Namespace Prefix: | mwa_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Income Tax Benefit, Likelihood of Realization Threshold + References No definition available. + Details
Name: | mwa_IncomeTaxBenefitLikelihoodOfRealizationThreshold
Namespace Prefix: | mwa_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Workers Compensation Undiscounted Basis Liability + References No definition available. + Details
Name: | mwa_WorkersCompensationUndiscountedBasisLiability
Namespace Prefix: | mwa_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Asset Retirement Obligation -URI http://asc.fasb.org/extlink&oid=6505190 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition For an unclassified balance sheet, the carrying amount (net of accumulated amortization) as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399 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 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 17 -Article 5 + Details
Name: | us-gaap_DeferredFinanceCostsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Carrying value as of the balance sheet date of obligations and payables pertaining to claims incurred of a workers compensation nature. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15(5)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.15(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 15 -Subparagraph a -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 15 -Subparagraph 5 -Article 9 + Details
Name: | us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant