XML 89 R74.htm IDEA: XBRL DOCUMENT v3.20.4

Pension and Post-Employment Benefits - Reconciliation of Fair Value of Plan Assets Measured Using Significant Unobservable Inputs (Detail) - United Kingdom Plan [Member] - Significant Unobservable Inputs (Level 3) [Member] - Other Assets [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 157.9	$ 142.5
Realized/unrealized gains/(losses):
Relating to assets still held at the reporting date	10.8	16.0
Purchases, issuances and settlements	(6.6)	(6.5)
Exchange effect	5.3	5.9
Ending balance	$ 167.4	$ 157.9

X

- Definition

Fair value measurement with unobservable inputs reconciliation recurring basis asset exchange effect.

+ References

No definition available.

+ Details

Name:	iosp_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetExchangeEffect
Namespace Prefix:	iosp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Fair value measurement with unobservable inputs reconciliation recurring basis asset gains and losses.

+ References

No definition available.

+ Details

Name:	iosp_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainsAndLossesAbstract
Namespace Prefix:	iosp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Fair value measurement with unobservable inputs reconciliation recurring basis asset still held gain loss included in earnings one.

+ References

No definition available.

+ Details

Name:	iosp_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetStillHeldGainLossIncludedInEarningsOne
Namespace Prefix:	iosp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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

X

- Definition

Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

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

X

- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

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

X

- Details

Name:	us-gaap_RetirementPlanNameAxis=iosp_UkPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_OtherAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: