Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from Operating Activities:
Net (loss) income	$ (2,506)	$ 16,733
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Depreciation and amortization	10,781	11,161
Deferred income tax expense	9,292	8,385
Provision for doubtful accounts	132	268
Non-cash share based compensation	6,641	4,885
Changes in operating assets and liabilities:
Cash restricted or segregated under regulations and other	(229)	187
Deposits with clearing organizations	(9,625)	(17,147)
Securities owned, at fair value	(329)	(544)
Receivables from brokers, dealers and clearing organizations	64,108	(237,220)
Receivables from customers	(21,797)	(2,090)
Accounts payable and accrued expenses	(17,929)	(35,315)
Payables to brokers, dealers and clearing organizations	(64,063)	188,964
Payables to customers	10,147	18,638
Securities sold, not yet purchased, at fair value	1,140	717
Income taxes receivable/payable	(14,299)	(8,551)
Excess tax benefit from share-based payment arrangements	(868)	(2,476)
Other, net	(3,205)	(2,448)
Net cash used in operating activities	(32,609)	(55,853)
Cash flows from Investing Activities:
Capital purchases	(2,782)	(1,399)
Capitalization of software development costs	(6,346)	(6,467)
Net cash used in investing activities	(9,128)	(7,866)
Cash flows from Financing Activities:
Repayments of long term debt	(1,465)	(3,169)
Proceeds from (repayments of) borrowing under short-term bank loans	(114)	28,908
Debt issuance costs	(807)
Excess tax benefit from share-based payment arrangements	868	2,476
Common stock issued	2,202	1,068
Common stock repurchased	(9,614)	(16,425)
Dividends paid	(2,297)
Shares withheld for net settlements of share-based awards	(6,295)	(8,069)
Net cash (used in) provided by financing activities	(17,522)	4,789
Effect of exchange rate changes on cash and cash equivalents	2,994	(10,518)
Net decrease in cash and cash equivalents	(56,265)	(69,448)
Cash and cash equivalents - beginning of year	330,653	275,210
Cash and cash equivalents - end of period	274,388	205,762
Supplemental cash flow information:
Interest paid	1,071	750
Income taxes paid	$ 3,949	$ 5,352