Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from Operating Activities:
Net income	$ 5,458	$ 9,549
Adjustments to reconcile net income to net cash used in operating activities
Depreciation and amortization	14,314	14,630
Deferred income tax expense	6,774	12,966
Provision for doubtful accounts	533	(88)
Share-based compensation	1,810	3,021
Changes in operating assets and liabilities:
Cash restricted or segregated under regulations and other	5,140	801
Deposits with clearing organizations	(4,599)	(3,154)
Securities owned, at fair value	(1,108)	16,020
Receivables from brokers, dealers and clearing organizations	(696,406)	(684,674)
Receivables from customers	(969,906)	(89,824)
Accounts payable and accrued expenses	(42,482)	(49,442)
Payables to brokers, dealers and clearing organizations	797,421	375,128
Payables to customers	770,302	365,164
Securities sold, not yet purchased, at fair value	1,044	(16,489)
Income taxes receivable/payable	(5,919)	(9,175)
Other, net	(5,628)	(2,054)
Net cash used in operating activities	(123,252)	(57,621)
Cash flows from Investing Activities:
Acquisitions of subsidiaries, net of cash acquired		(144)
Capital purchases	(4,150)	(5,630)
Capitalization of software development costs	(6,929)	(9,266)
Proceeds from sale of investments		2,095
Net cash used in investing activities	(11,079)	(12,945)
Cash flows from Financing Activities:
Repayments of long term debt	(1,738)
Proceeds from borrowing under short-term bank loans	84,930	34,207
Debt issuance costs		(2,603)
Common stock issued	2,670	5,446
Common stock repurchased	(9,062)	(12,630)
Shares withheld for net settlements of share-based awards	(2,250)	(4,799)
Net cash provided by financing activities	74,550	19,621
Effect of exchange rate changes on cash and cash equivalents	(1,375)	947
Net decrease in cash and cash equivalents	(61,156)	(49,998)
Cash and cash equivalents - beginning of year	284,188	317,010
Cash and cash equivalents - end of period	223,032	267,012
Supplemental cash flow information
Interest paid	691	335
Income taxes paid	$ 2,146	$ 3,757