Income Taxes - Impact From the Singapore Tax Concession (Details) - Inland Revenue, Singapore (IRAS) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Increase (Decrease) Foreign Income Taxes Tax Concession [Line Items]
Singapore tax concession impact on foreign income tax	$ (1.1)	$ (2.4)	$ (4.3)
Impact on basic earnings per share (in dollars per share)	$ (0.02)	$ (0.04)	$ (0.07)
Impact on diluted earnings per share (in dollars per share)	$ (0.02)	$ (0.04)	$ (0.06)

Income Tax Concession, Impact On Foreign Income Tax Expense (Benefit)

No definition available.

Name:	int_IncomeTaxConcessionImpactOnForeignIncomeTaxExpenseBenefit
Namespace Prefix:	int_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration