Partners' Capital (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
Partners' Capital (Narrative) (Details) (USD $)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Limited Partners' Capital Account [Line Items]
Limited Partners' capital account, units issued	14,985,550		14,985,550		14,985,550
Limited Partners' capital account, units outstanding	14,985,550		14,985,550		14,985,550
Limited Partners' capital account, units authorized	15,000,000		15,000,000		15,000,000
Partnership right to repurchase units of a unitholder			100.00%
Percentage of cash distributions from operations as incentive management fee			4.00%
Weighted average distributions per unit	$ 0	$ 0	$ 0	$ 0	$ 0.18
First [Member]
Limited Partners' Capital Account [Line Items]
Percentage of cash distributions from sales or refinancing as annual return on invested capital			10.00%
Initial Limited Partners [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' capital account, units issued	50		50		50
Limited Partner [Member]
Limited Partners' Capital Account [Line Items]
Allocation of net income, net losses, and distributions			92.50%
Limited Partner [Member] \| First [Member]
Limited Partners' Capital Account [Line Items]
Percentage of cash distributions from operations			88.50%
Percentage of cash distribution from sales or refinancing			92.50%
Limited Partner [Member] \| Thereafter [Member]
Limited Partners' Capital Account [Line Items]
Percentage of cash distributions from sales or refinancing as annual return on invested capital			10.00%
Limited Partner [Member] \| Second [Member]
Limited Partners' Capital Account [Line Items]
Percentage of cash distributions from operations			85.00%
Percentage of cash distribution from sales or refinancing			85.00%
General Partner [Member]
Limited Partners' Capital Account [Line Items]
Allocation of net income, net losses, and distributions			7.50%
General Partner [Member] \| First [Member]
Limited Partners' Capital Account [Line Items]
Percentage of cash distributions from operations			7.50%
Percentage of cash distribution from sales or refinancing			7.50%
General Partner [Member] \| Second [Member]
Limited Partners' Capital Account [Line Items]
Percentage of cash distributions from operations as incentive management fee			7.50%
Percentage of cash distribution from sales or refinancing			7.50%
Affiliated Entity [Member] \| First [Member]
Limited Partners' Capital Account [Line Items]
Percentage of cash distributions from operations			4.00%
Affiliated Entity [Member] \| Second [Member]
Limited Partners' Capital Account [Line Items]
Percentage of cash distributions from operations as incentive management fee			7.50%
Percentage of cash distribution from sales or refinancing			7.50%

ATEL CAPITAL EQUIPMENT FUND VII LP 10-Q