Annual report pursuant to Section 13 and 15(d)

Consolidated Valuation and Qualifying Accounts (Parenthetical) (Detail)

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Consolidated Valuation and Qualifying Accounts (Parenthetical) (Detail) (Allowance for Doubtful Accounts, USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Valuation and Qualifying Accounts Disclosure [Line Items]      
Deductions from accounts receivable allowance $ 809 [1] $ 660 [1] $ 777 [1]
Real Goods Solar Deconsolidated
      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Deductions from accounts receivable allowance   $ 500  
[1] The 2011 deduction amount for the allowance for doubtful accounts includes $0.5 million related to the deconsolidation of Real Goods Solar. See Note 3. Equity Method Investment and Receivable From Investee