Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 30,204	$ 7,854
Non-cash items included in net income:
Income tax benefit	(13,725)
Depreciation and amortization and other	192	82
Stock-based compensation	2,015	1,714
Deferred rent	643	(34)
Accretion to interest income and other	(111)	39
Changes in operating assets and liabilities:
Accounts receivable	285	(1,750)
Other assets	(491)	(256)
Fund management and administration payable	1,358	2,589
Compensation and benefits payable	(11,473)	457
Accounts payable and other liabilities	537	(451)
Net cash provided by operating activities	9,434	10,244
Cash flows from investing activities:
Purchase of fixed assets	(3,527)	(10)
Purchase of investments	(154)	(1,314)
Proceeds from the redemption of investments	61	1,633
Net cash (used in)/provided by investing activities	(3,620)	309
Cash flows from financing activities:
Shares repurchased	(5,426)	(249)
Proceeds from exercise of stock options	76	747
Net cash (used in)/provided by financing activities	(5,350)	498
Net increase in cash and cash equivalents	464	11,051
Cash and cash equivalents-beginning of period	104,316	41,246
Cash and cash equivalents-end of period	104,780	52,297
Supplemental disclosure of cash flow information:
Cash paid for taxes	$ 14	$ 34