EMPLOYEE BENEFIT PLAN (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
SMART Plan
Defined Contribution Plan
Balance amount in the plan	$ 18.4
Company contribution amount	$ 1.5	$ 1.6
Cboe Europe Equities Employee Selected Stakeholder Contribution Plan
Defined Contribution Plan
Company contribution amount		$ 0.2

Amount of cost for defined contribution plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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