Components of Operating Expenses (Detail) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Component of Operating Other Cost and Expense [Line Items]
Fixed compensation expense	$ 3,797	$ 3,890	$ 7,942	$ 8,080
Variable compensation expense	646	1,303	1,246	3,183
Equity compensation expense	2,707	2,077	4,766	8,136
Total compensation expense	7,150	7,270	13,954	19,399
Systems	1,915	1,734	3,854	3,311
Office costs	1,582	1,783	3,322	3,548
Accounting and legal	908	45	1,544	1,511
Other operating expenses	532	395	926	764
Total Operating Expenses	$ 12,087	$ 11,227	$ 23,600	$ 28,533

Fixed Compensation Expense

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Variable Compensation Expense

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The amount of expense in the period for communications and data processing expense.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

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The aggregate amount of expenditures for salaries, wages, profit sharing and incentive compensation, and other employee benefits, including equity-based compensation, and pension and other postretirement benefit expense.

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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A fee charged for services from professionals such as doctors, lawyers and accountants. The term is often expanded to include other professions, for example, pharmacists charging to maintain a medicinal profile of a client or customer.

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