Variable Interest Entities- Additional Information (Details)	9 Months Ended
	Sep. 30, 2021 joint_venture
Variable Interest Entity [Line Items]
Number of joint ventures considered as VIEs	4
JV building microwave communication networks in US, Europe and Asia
Variable Interest Entity [Line Items]
Number of joint ventures	2
JV building microwave communication networks in US and Asia
Variable Interest Entity [Line Items]
Ownership of equity of JV held be each investor (as a percent)	10.00%
JV building microwave communication networks in US and Europe
Variable Interest Entity [Line Items]
Ownership interest	50.00%
JV offering derivatives trading technology and execution services
Variable Interest Entity [Line Items]
Ownership interest	10.00%
JV developing a member-owned equities exchange with the goal of increasing competition
Variable Interest Entity [Line Items]
Ownership interest	14.10%