Investment in Leases (Detail) (USD $)
In Thousands, unless otherwise specified
 9 Months Ended
Sep. 30, 2012
Leases Disclosure [Line Items]  
Balance December 31, 2011 $ 8,276
Reclassifications & Additions / Dispositions (59)
Depreciation/ Amortization Expense or Amortization of Leases (970)
Balance September 30, 2012 7,247
Operating leases
  
Leases Disclosure [Line Items]  
Balance December 31, 2011 7,867
Reclassifications & Additions / Dispositions (602)
Depreciation/ Amortization Expense or Amortization of Leases (827)
Balance September 30, 2012 6,438
Direct financing leases
  
Leases Disclosure [Line Items]  
Balance December 31, 2011 256
Reclassifications & Additions / Dispositions (3)
Depreciation/ Amortization Expense or Amortization of Leases (123)
Balance September 30, 2012 130
Assets held for sale or lease
  
Leases Disclosure [Line Items]  
Balance December 31, 2011 153
Reclassifications & Additions / Dispositions 546
Depreciation/ Amortization Expense or Amortization of Leases (20)
Balance September 30, 2012 $ 679