Future Minimum Lease Payments (Details Textual)	12 Months Ended
	Dec. 31, 2012 Person	Dec. 31, 2011	Dec. 31, 2010
Future Minimum Lease Payments (Textual) [Abstract]
Minimum contribution of base rental revenues per tenant	34.00%	48.00%	74.00%
Total contribution of base rental	19.70%	21.80%	44.00%
Percentage of tenant of the total rentable square footage	17.50%	14.50%	43.00%
Number of major customers	3