Fair Value of Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014 Technique	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of valuation techniques	3mtx_NumberOfValuationTechniques
Transfers in or out of Level 3	$ 0	$ 0
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward exchange contracts	0.5
Forward exchange contracts	(0.3)
Deferred compensation plan assets	12.6
Supplementary pension plan assets	9.9
Money market funds		203.2
Fair Value, Measurements, Recurring [Member] \| Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward exchange contracts	0
Forward exchange contracts	0
Deferred compensation plan assets	0
Supplementary pension plan assets	0
Money market funds		203.2
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward exchange contracts	0.5
Forward exchange contracts	(0.3)
Deferred compensation plan assets	12.6
Supplementary pension plan assets	9.9
Money market funds		0
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward exchange contracts	0
Forward exchange contracts	0
Deferred compensation plan assets	0
Supplementary pension plan assets	0
Money market funds		$ 0

Fair value portion of asset contracts related to deferred compensation plan.

No definition available.

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- Definition

Refers to number of valuation techniques for assets and liabilities measured at fair value.

+ References

No definition available.

+ Details

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- Definition

Fair value portion of asset contracts related to supplementary pension plan.

+ References

No definition available.

+ Details

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

+ Details

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- Details

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- Definition

Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy.

+ References

No definition available.

+ Details

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- Definition

Fair value portion of asset contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward contracts, and swaps.

+ References

No definition available.

+ Details

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- Definition

Fair value portion of liability contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward (delivery or nondelivery) contracts, and swaps entered into.

+ References

No definition available.

+ Details

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- Details

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