Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities:
Net income/(loss)	$ (22,255)	$ 18,806
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Depreciation and amortization of fixed assets	2,632	2,392
Deferred income taxes	(11,325)	13,855
Stock-based compensation	21,795	4,350
Amortization of intangible assets	9,878	2,112
Amortization of forgivable loans	1,068	1,503
Decrease/(increase) in operating assets:
Receivables from brokers, dealers and clearing organizations	458,821	188,268
Net financial instruments and other inventory positions owned	(9,888)	(17,359)
Investments	17,284	(62)
Other assets	(13,937)	(3,936)
Increase/(decrease) in operating liabilities:
Payables to brokers, dealers and clearing organizations	8,687	(2,385)
Accrued compensation	(222,256)	(163,104)
Other liabilities and accrued expenses	(2,912)	(8,318)
Increase in assets held for sale	0	(383)
Decrease in liabilities held for sale	0	(7,218)
Net cash provided by operating activities	237,592	28,521
Investing Activities:
Business acquisitions, net of cash acquired	(371,369)	0
Purchases of fixed assets, net	(2,359)	(1,421)
Net cash used in investing activities	(373,728)	(1,421)
Financing Activities:
Increase in short-term financing	50,002	3
Payment of cash dividend	(16,066)	(19,947)
Decrease in noncontrolling interests	(1,201)	(5)
Repurchase of common stock	(17,293)	(39,727)
Net cash provided by/(used in) financing activities	15,442	(59,676)
Currency adjustment:
Effect of exchange rate changes on cash	(742)	457
Net decrease in cash and cash equivalents	(121,436)	(32,119)
Cash and cash equivalents at beginning of period	250,018	50,364
Cash and cash equivalents at end of period	128,582	18,245
Supplemental disclosure of cash flow information:
Interest	4,127	2,809
Income taxes	$ 557	$ 7,462