Partners' Capital (Narrative) (Details)	3 Months Ended
Partners' Capital (Narrative) (Details)	Mar. 31, 2013	Dec. 31, 2012
Other Members Capital Account [Line Items]
Limited Partners' capital account, units issued	14,985,550	14,985,550
Limited Partners' capital account, units outstanding	14,985,550	14,985,550
Limited Partners' capital account, units authorized	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%
Initial Limited Partners [Member]
Other Members Capital Account [Line Items]
Limited Partners' capital account, units issued	50	50
Limited Partner [Member]
Other Members Capital Account [Line Items]
Allocation of net income, net losses, and distributions	92.50%
General Partner [Member]
Other Members Capital Account [Line Items]
Allocation of net income, net losses, and distributions	7.50%
First [Member]
Other Members Capital Account [Line Items]
Percentage of cash distributions from sales or refinancing as annual return on invested capital	10.00%
First [Member] \| Limited Partner [Member]
Other Members Capital Account [Line Items]
Percentage of cash distributions from operations	88.50%
Percentage of cash distribution from sales or refinancing	92.50%
First [Member] \| General Partner [Member]
Other Members Capital Account [Line Items]
Percentage of cash distributions from operations	7.50%
Percentage of cash distribution from sales or refinancing	7.50%
First [Member] \| Affiliated Entity [Member]
Other Members Capital Account [Line Items]
Percentage of cash distributions from operations	4.00%
Thereafter [Member] \| Limited Partner [Member]
Other Members Capital Account [Line Items]
Percentage of cash distributions from sales or refinancing as annual return on invested capital	10.00%
Second [Member] \| Limited Partner [Member]
Other Members Capital Account [Line Items]
Percentage of cash distributions from operations	85.00%
Percentage of cash distribution from sales or refinancing	85.00%
Second [Member] \| General Partner [Member]
Other Members 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%
Second [Member] \| Affiliated Entity [Member]
Other Members 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