Gain Contingencies (Narrative) (Details) (USD $)	6 Months Ended
Jun. 30, 2013 item
Gain Contingencies [Line Items]
Gain Contingency, unrecorded amount	$ 2,800,000
Fleet Manager [Member]
Gain Contingencies [Line Items]
Gain Contingency, unrecorded amount	2,800,000
Gain contingency, number of vessels	3
Gain contingency, percentage of fross proceeds	10.00%
Fleet Manager [Member] \| ATEL Capital Equipment Fund VII, L.P. [Member]
Gain Contingencies [Line Items]
Gain Contingency, unrecorded amount	1,400,000
Legal fees and costs	$ 350,000

The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.3)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Name:	us-gaap_LegalFees
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration