Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from Operating Activities:
Net income	$ 8,622	$ 5,458
Adjustments to reconcile net income to net cash used in operating activities
Depreciation and amortization	13,344	14,314
Deferred income tax expense	1,205	6,774
Provision for doubtful accounts	(157)	533
Share-based compensation	5,525	1,810
Changes in operating assets and liabilities:
Cash restricted or segregated under regulations and other	843	5,140
Deposits with clearing organizations	4,801	(4,599)
Securities owned, at fair value	(1,453)	(1,108)
Receivables from brokers, dealers and clearing organizations	(1,013,541)	(696,406)
Receivables from customers	(828,512)	(969,906)
Accounts payable and accrued expenses	(18,280)	(42,482)
Payables to brokers, dealers and clearing organizations	1,087,076	797,421
Payables to customers	716,571	770,302
Securities sold, not yet purchased, at fair value	1,399	1,044
Income taxes receivable/payable	9,178	(5,919)
Excess tax benefit from share-based payment arrangements	(156)
Other, net	(3,182)	(5,628)
Net cash used in operating activities	(16,717)	(123,252)
Cash flows from Investing Activities:
Capital purchases	(15,784)	(4,150)
Capitalization of software development costs	(5,782)	(6,929)
Net cash used in investing activities	(21,566)	(11,079)
Cash flows from Financing Activities:
Repayments of long term debt	(1,856)	(1,738)
Proceeds from term loans	18,157
Proceeds from borrowing under short-term bank loans	25,339	84,930
Excess tax benefit from share-based payment arrangements	156
Common stock issued	482	2,670
Common stock repurchased	(8,953)	(9,062)
Shares withheld for net settlements of share-based awards	(3,562)	(2,250)
Net cash provided by financing activities	29,763	74,550
Effect of exchange rate changes on cash and cash equivalents	(3,457)	(1,375)
Net decrease in cash and cash equivalents	(11,977)	(61,156)
Cash and cash equivalents - beginning of year	245,875	284,188
Cash and cash equivalents - end of period	233,898	223,032
Supplemental cash flow information
Interest paid	688	691
Income taxes (refunded) paid	$ (8,018)	$ 2,146