Contingent consideration to related parties.

No definition available.

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- Definition

Total costs of sales and operating expenses for the period.

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Indicates designation of financial information when substantially all business or separately identifiable line of business transfers from one entity to another entity. Acceptable values are "Predecessor" and "Successor".

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The net result for the period of deducting operating expenses from operating revenues.

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No definition available.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Business Segment and Geographic Information - Revenue by Client Sector (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Segment and Geographic Information
Financial Designation, Predecessor and Successor [Fixed List]	Successor	Successor	Successor	Predecessor	Successor	Successor	Predecessor
Gross revenues		$ 178,637		$ 505,771	$ 775,566		$ 562,968
Contingent consideration				(26,830)			(58,520)
Net revenue		178,637		478,941	775,566		504,448
Operating expenses		146,702		338,607	585,747		415,356
Operating income		31,935		140,334	189,819		89,092
Institutional
Business Segment and Geographic Information
Gross revenues		103,971		301,918	453,379		318,038
Wholesale
Business Segment and Geographic Information
Gross revenues		38,153		99,028	171,096		118,451
Retail
Business Segment and Geographic Information
Gross revenues		19,780		57,766	80,368		70,857
Market Data
Business Segment and Geographic Information
Gross revenues		$ 16,733		$ 47,059	$ 70,723		$ 55,622