Annual report pursuant to Section 13 and 15(d)

Financing Receivables and Investments - Additional Information (Detail)

v2.4.0.8
Financing Receivables and Investments - Additional Information (Detail) (USD $)
 3 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended
Dec. 31, 2012
Dec. 31, 2013
Sep. 30, 2012
Sep. 30, 2011
Dec. 31, 2013
Berkshire Hathaway Inc [Member]
Dec. 31, 2013
EnergySource LLC [Member]
May 31, 2013
EnergySource LLC [Member]
Dec. 31, 2013
Finance Receivables One [Member]
Dec. 31, 2013
Finance Receivables Two [Member]
Financing Receivable, Recorded Investment [Line Items]                  
Investments with unrealized loss position   $ 0              
Investments   91,964,000               
Financing receivable held for sale, carrying value and fair value   27,971,000               
Amortizing government receivables maturity date               2032-07-31 2037-10-31
Debt security, carrying value         3,200,000        
Investments held-for-sale     0            
Deferred funding obligations   74,700,000 0            
Restricted cash   49,865,000 2,035,000            
Credit agreement amount             24,000,000    
Interest rate, paid quarterly in cash           15.22% 15.22%    
Remaining outstanding balance   14,000,000       11,800,000      
Repayment of loan           14,000,000      
Financial receivable average outstanding balance           24,700,000      
Accrued interest income   2,400,000              
Fund contribution received from equity holders   31,000,000              
Financing receivable allowance for credit losses   11,000,000 0            
Maximum exposure loss for variable interest entity   800,000              
Other financing receivables on non accrual status   0              
Provision for credit losses $ 0   $ 0 $ 0