Gain Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 item
Gain Contingencies [Line Items]
Gain contingency, unrecorded amount	$ 2.8
Fleet Manager [Member]
Gain Contingencies [Line Items]
Gain contingency, unrecorded amount	2.8
Gain contingency, number of vessels	3
Gain contingency, percentage of gross proceeds	10.00%
Fleet Manager [Member] | ATEL Capital Equipment Fund VII, L.P. [Member]
Gain Contingencies [Line Items]
Gain contingency, unrecorded amount	$ 1.4