EMPLOYEE BENEFIT PLAN (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
SMART Plan
Defined Contribution Plan
Total assets in the trust	$ 24,000,000.0		$ 24,500,000
Company contribution amount	2,200,000	$ 1,500,000
Cboe Europe Equities Employee Selected Stakeholder Contribution Plan
Defined Contribution Plan
Company contribution amount	400,000	$ 200,000
EuroCCP
Defined Contribution Plan
Company contribution amount	200,000
Cboe Canadian Retirement Plan
Defined Contribution Plan
Company contribution amount	$ 28,700