Commitments and Contingencies UNL Construction (Details) (USD $)	3 Months Ended
	Mar. 31, 2013 parkingstalls
Construction in Progress [Member]
Operating Leases, Rent Expense	$ 100
Number of Parking Stalls	1,605
Estimated Total Cost of Construction	34,000,000
Possible Penalty on Construction	6,000
Construction in Progress [Member] | 3 year term [Member]
Estimated Debt of Construction	25,500,000
Construction in Progress [Member] | 5 year term [Member]
Debt Instrument, Interest Rate, Stated Percentage	4.70%
Estimated Debt of Construction	4,300,000
Construction in Progress [Member]
Operating Leases, Rent Expense	100
Number of Parking Stalls	1,605
Number of Units in Real Estate Property	475
Estimated Total Cost of Construction	34,000,000
Estimated Debt of Construction	$ 29,800,000