| Selected Balance Sheet Data - Components of Commissions Receivable, Net (Detail) (USD $) In Thousands, unless otherwise specified | Mar. 31, 2014 | Dec. 31, 2013 | Mar. 31, 2013 | Dec. 31, 2012 | 
|---|---|---|---|---|
| Balance Sheet Related Disclosures [Abstract] | ||||
| Commissions due from buyer/seller | $ 2,296 | $ 3,241 | ||
| Due from independent contractors | 1,094 | 973 | ||
| Less allowance for doubtful accounts | (81) | (99) | (129) | (129) | 
| Commissions receivable | $ 3,309 | $ 4,115 | 
| X | ||||||||||
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- Definition Amount due for commissions from buyers and sellers. No definition available. 
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| X | ||||||||||
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- Definition Amount due for commissions from buyers/sellers and current receivables from independent contractors (i.e. Company's sales and financing professionals), net of allowance for doubtful accounts. No definition available. 
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| X | ||||||||||
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- Definition Amount due from independent contractors. No definition available. 
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| X | ||||||||||
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- Definition A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Details 
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