Restructuring and impairment charges - Charges Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 29, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,346	$ 14,365
Asset impairment charges		3,030
Restructuring and impairment charges	1,346	17,395
Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,036	13,538
Asset impairment charges		0
Restructuring and impairment charges		13,538
Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	310	827
Asset impairment charges		3,030
Restructuring and impairment charges		3,857
2019 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	838	12,975
2019 Footprint realignment plan \| Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	829	12,975
2019 Footprint realignment plan \| Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	9	0
2018 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	395	1,011
2018 Footprint realignment plan \| Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	314	437
2018 Footprint realignment plan \| Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	81	574
Other restructuring programs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	113	379
Other restructuring programs \| Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(107)	126
Other restructuring programs \| Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 220	$ 253

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228

+ Details

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RestructuringCostAndReserveLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of restructuring charges, remediation cost, and asset impairment loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

+ Details

Name:	us-gaap_RestructuringSettlementAndImpairmentProvisions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=tfx_SeveranceAndTerminationBenefitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_OtherRestructuringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=tfx_TwoThousandNineteenFootprintRealignmentPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=tfx_TwoThousandEighteenFootprintRealignmentPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=tfx_OtherrestructuringprogramsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: