| Contracts Receivable and Retainage - Additional Information (Detail) (USD $) | 9 Months Ended | ||
|---|---|---|---|
| Sep. 30, 2013 | Dec. 31, 2012 | Sep. 30, 2013
 Top 3 Customer
 Customer | |
| Long-term Contracts or Programs Disclosure [Line Items] | |||
| Contract receivable | $ 75,130,000 | $ 60,535,000 | $ 54,500,000 | 
| Number of major customers account for 0% of contract receivable | 3 | ||
| Percentage of contract receivable | 72.30% | ||
| Reserve for bad debt | $ 800,000 | 
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- Details 
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- Definition Number Of Major Customer Revenue No definition available. 
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- Definition Percentage Of Revenue From Major Customer No definition available. 
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- Definition For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount billed to customers under long-term contracts or programs to be collected in the next fiscal year following the latest fiscal year. Excludes amounts due that have been withheld because of retainage provisions in a contract. No definition available. 
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