Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 63,255	$ 67,896	$ 54,277
Adjustments to reconcile net income to net cash provided by operating activities:
Stock compensation expense	21,539	17,562	18,675
Amortization, deferred commissions	3,009	2,341	1,744
Depreciation and amortization	5,606	5,562	5,056
Deferred rent	1,954	711	(530)
Loss (gain) from trading securities—net	6,612	(4,082)	(39)
Equity in (earnings) losses of affiliates	(840)	(1,050)	3,021
Gain from available-for-sale securities—net	(2,259)	(1,237)	(376)
Deferred income taxes	(3,087)	(173)	(415)
Foreign currency loss (gain)	622	572	(829)
Changes in operating assets and liabilities:
Accounts receivable	2,887	(5,379)	(5,940)
Due from broker	(8,826)	(10,562)	(3,699)
Deferred commissions	(2,399)	(2,981)	(1,915)
Securities owned	(11,573)	(65,347)	7,393
Other assets	1,542	(1,655)	(1,597)
Accrued compensation	(152)	3,039	3,445
Securities sold but not yet purchased	(14,685)	6,251	(599)
Income tax payable	(1,026)	4,445	(4,388)
Other liabilities and accrued expenses	13,693	4,430	(839)
Net cash provided by operating activities	75,872	20,343	72,445
Cash flows from investing activities:
Proceeds from redemption of equity method investments	7,741	811	8,800
Purchases of investments, available-for-sale	(10,195)	(20,733)	(37,611)
Proceeds from sales of investments, available-for-sale	26,700	25,736	28,703
Purchases of property and equipment	(6,230)	(3,361)	(2,927)
Net cash provided by (used in) investing activities	18,016	2,453	(3,035)
Cash flows from financing activities:
Excess tax benefits associated with restricted stock units	2,025	2,905	1,483
Issuance of common stock	408	439	466
Repurchase of common stock	(7,962)	(8,484)	(6,647)
Dividends to stockholders	(79,695)	(97,208)	(69,118)
Redemptions of redeemable noncontrolling interest	(14,242)	(8,438)	(3,734)
Contributions from redeemable noncontrolling interest	37,711	55,132	0
Net cash used in financing activities	(61,755)	(55,654)	(77,550)
Net increase (decrease) in cash and cash equivalents	32,133	(32,858)	(8,140)
Effect of foreign exchange rate changes on cash and cash equivalents	732	446	(227)
Cash and cash equivalents, beginning of the year	95,412	127,824	136,191
Cash and cash equivalents, end of the year	$ 128,277	$ 95,412	$ 127,824