XML 90 R75.htm IDEA: XBRL DOCUMENT v3.10.0.1

Income Taxes - Net Operating Losses and Income Tax Concessions (Details) - USD ($) $ in Millions			12 Months Ended
	Jan. 01, 2018	Jan. 01, 2013	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income taxes
Net operating losses			$ 275.3	$ 240.3
Net operating loss carryforward			33.7	23.0
Valuation allowance			24.3	24.6
Period applicable for additional special income tax concession		5 years
Period applicable for additional special income tax concession, renewal term	5 years
Unrecognized Tax Benefits			57.0	58.8	$ 62.2	$ 47.8
Gross increases – tax positions in prior period			3.6	10.9	19.7
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions			10.6	0.0	15.4
Gross increases – tax positions in current period			11.5	10.7	12.9
Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions			0.0	0.0	0.0
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities			1.5	23.0	0.0
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations			4.8	$ 2.1	$ 2.8
December 31, 2020
Income taxes
Net operating loss carryforward
December 31, 2021
Income taxes
Net operating loss carryforward			0.3
December 31, 2022
Income taxes
Net operating loss carryforward			0.7
December 31, 2023
Income taxes
Net operating loss carryforward			0.7
December 31, 2024
Income taxes
Net operating loss carryforward			0.4
December 31, 2025
Income taxes
Net operating loss carryforward			0.4
December 31, 2026
Income taxes
Unrecognized Tax Benefits			0.4
December 31, 2027
Income taxes
Gross increases – tax positions in prior period			0.4
December 31, 2028
Income taxes
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions			0.3
December 31, 2029
Income taxes
Gross increases – tax positions in current period			0.6
December 31, 2030
Income taxes
Gross increases – tax positions in current period			0.4
December 31, 2031
Income taxes
Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions			0.2
December 31, 2032
Income taxes
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities			0.4
December 31, 2033
Income taxes
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations			0.3
December 31, 2034
Income taxes
Unrecognized Tax Benefits			0.3
December 31, 2035
Income taxes
Net operating loss carryforward			0.5
December 31, 2036
Income taxes
Net operating loss carryforward			2.6
December 31, 2037
Income taxes
Net operating loss carryforward			4.1
December 31, 2038
Income taxes
Net operating loss carryforward			3.3
Indefinite
Income taxes
Net operating loss carryforward			$ 17.4

X

- Definition

Represents the period applicable for income tax concession.

+ References

No definition available.

+ Details

Name:	int_PeriodApplicableIncomeTaxConcession
Namespace Prefix:	int_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Period Applicable Income Tax Concession, Renewal Term

+ References

No definition available.

+ Details

Name:	int_PeriodApplicableIncomeTaxConcessionRenewalTerm
Namespace Prefix:	int_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 25
-Paragraph 20
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=115928272&loc=d3e28680-109314

+ Details

Name:	us-gaap_DeferredTaxAssetsOperatingLossCarryforwards
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

+ Details

Name:	us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319

+ Details

Name:	us-gaap_OperatingLossCarryforwards
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

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

X

- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 10B
-URI http://asc.fasb.org/extlink&oid=84176650&loc=SL37586934-109318

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

Name:	us-gaap_UnrecognizedTaxBenefits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount of decrease in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

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

X

- Definition

Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

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

X

- Definition

Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

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

X

- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)(4)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

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

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2029Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2030Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2031Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2032Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2033Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2034Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2035Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2036Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2037Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_ExpirationOn31December2038Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	int_DeferredTaxAssetExpirationDateAxis=int_IndefiniteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: