Acquisitions (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013 sqft	Jun. 30, 2012	Jun. 30, 2013 sqft	Jun. 30, 2012	Mar. 31, 2013
Business Acquisition Area of Land	1,600,000		1,600,000
Percentage Of Land Leased	100.00%		100.00%
Business Acquistion Real Estate Assets	$ 97,200		$ 97,200		$ 50,272
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets					9,730
Business Acquistion Purchase Price Allocation Intangible Liabilities					3,679
Business Acquistion Purchase Price Reallocation Intangible Assets And Liabilities	4,207		4,207
Revenue Towards Acquisition	1,342		1,457
Net Income Towards Acquisition		495		581
Hutchins, Texas [Member]
Business Acquistion Real Estate Assets	26,322		26,322
Business Acquistion Real Estate Assets Fair Value	29,385		29,385
Capitalized Loan Assumption Costs	263		263
Build to suit property [Member]
Business Acquisition Area of Land	120,000		120,000
Percentage Of Land Leased	100.00%		100.00%
Mortgage Note Payable	4,990		4,990
Acquisition Costs Of Land	25,000		25,000
Unfunded Amount Towards Land Cost	$ 23,158		$ 23,158