Regulatory Requirements (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)
Regulatory Requirements
Proceeds from Contributions from Parent	$ 3,000,000.0
Securities Registered Domestically
Regulatory Requirements
Net Capital	3,500,000
Excess Capital	3,300,000
Securities Regulated By Foreign Entities - Asia [Member]
Regulatory Requirements
Net Capital	10,400,000
Excess Capital	10,000,000.0
Securities Regulated By Foreign Entities - UK [Member]
Regulatory Requirements
Net Capital	38,200,000
Excess Capital	32,500,000
Securities Regulated By Foreign Entities - Japan [Member] [Domain]
Regulatory Requirements
Net Capital	$ 460,000