Condensed Consolidated Statements of Financial Condition (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Assets
Cash and cash equivalents	$ 233,898	$ 245,875
Cash restricted or segregated under regulations and other	59,768	61,117
Deposits with clearing organizations	24,348	29,149
Securities owned, at fair value	11,515	10,086
Receivables from brokers, dealers and clearing organizations	2,112,042	1,107,119
Receivables from customers	1,362,041	546,825
Premises and equipment, net	65,607	54,989
Capitalized software, net	42,205	43,994
Other intangibles, net	34,152	35,227
Income taxes receivable	2	7,460
Deferred taxes	36,763	39,155
Other assets	19,022	15,763
Total assets	4,001,363	2,196,759
Liabilities:
Accounts payable and accrued expenses	148,052	165,062
Short-term bank loans	47,494	22,154
Payables to brokers, dealers and clearing organizations	2,412,090	1,337,459
Payables to customers	935,072	226,892
Securities sold, not yet purchased, at fair value	6,623	5,249
Income taxes payable	12,134	10,608
Deferred taxes	226	293
Term debt	35,574	19,272
Total liabilities	3,597,265	1,786,989
Commitments and contingencies
Stockholders' Equity:
Preferred stock, $0.01 par value; 1,000,000 shares authorized; no shares issued or outstanding
Common stock, $0.01 par value; 100,000,000 shares authorized; 52,105,402 and 52,037,011 shares issued at March 31, 2013 and December 31, 2012, respectively	521	520
Additional paid-in capital	234,375	245,002
Retained earnings	414,107	405,485
Common stock held in treasury, at cost; 14,893,575 and 14,677,872 shares at March 31, 2013 and December 31, 2012, respectively	(251,485)	(253,111)
Accumulated other comprehensive income (net of tax)	6,580	11,874
Total stockholders' equity	404,098	409,770
Total liabilities and stockholders' equity	$ 4,001,363	$ 2,196,759