INVESTMENTS IN NON-CONSOLIDATED COMPANIES (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure of interests in other entities [Abstract]
Investments in non-consolidated companies, beginning balance	$ 478,348	$ 418,379
Equity in earnings (losses) of non-consolidated companies	102,772	68,115
Other comprehensive income	(77,042)	(4,786)
Dividends from non-consolidated companies	(8,837)	(3,360)
Investments in non-consolidated companies, ending balance	$ 495,241	$ 478,348

The cash inflow representing dividends received from investments that are accounted for using the equity method, classified as investing activities. [Refer: Investments accounted for using equity method; Dividends received]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2017-01-01
-Paragraph 16
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_16&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_DividendsReceivedFromInvestmentsAccountedForUsingEquityMethodClassifiedAsInvestingActivities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2017-01-01
-Paragraph 24
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2017-03-01&anchor=para_24_a&doctype=Standard
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2017-01-01
-Paragraph B16
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_B16&doctype=Appendix&seq=2
-URIDate 2017-03-09

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 54
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_54_e&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_InvestmentAccountedForUsingEquityMethod
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The entity's share of the profit (loss) of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Investments accounted for using equity method; Joint ventures [member]; Profit (loss)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2017-01-01
-Paragraph 23
-Subparagraph g
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2017-03-01&anchor=para_23_g&doctype=Standard
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2017-01-01
-Paragraph 28
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2017-03-01&anchor=para_28_e&doctype=Standard
-URIDate 2017-03-09

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 82
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_82_c&doctype=Standard
-URIDate 2017-03-09

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective on first application of IFRS 9
-Name IFRS
-Number 4
-IssueDate 2017-01-01
-Paragraph 39M
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=4&date=2017-03-01&anchor=para_39M_b&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The entity's share of the total comprehensive income of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Joint ventures [member]; Investments accounted for using equity method]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2017-01-01
-Paragraph B16
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_B16_d&doctype=Appendix&seq=2
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_ShareOfTotalComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethod
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Disclosure of interests in other entities [Abstract]

+ References

No definition available.

+ Details

Name:	tx_DisclosureofinterestsinotherentitiesAbstract
Namespace Prefix:	tx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration