Property Transactions Property Transactions (Details) (USD $)						9 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Aug. 08, 2014 sqft	Mar. 11, 2014	Dec. 31, 2013	Apr. 12, 2013	Sep. 30, 2014 Lakeshore Park Plaza Birmingham [Member] sqft	Dec. 31, 2013 Lakeshore Park Plaza Birmingham [Member] sqft	Sep. 30, 2014 Six Hundred University Park Place Birmingham [Member] sqft	Dec. 31, 2013 Six Hundred University Park Place Birmingham [Member] sqft	Dec. 31, 2013 Tiffany Springs MarketCenter Kansas City [Member] sqft	Dec. 31, 2013 Inhibitex Suburban Atlanta [Member] sqft	Sep. 30, 2014 Fifth Third Center [Member]	Oct. 01, 2014 Subsequent Event [Member] Northpark Town Center [Member] sqft
Business Acquisition [Line Items]
Common Stock, Shares, Issued	220,078,986	18,000,000	8,700,000	193,236,454	16,500,000
Business Acquisition Purchase Price Allocation Tangible Assets Land												$ 22,863,000
Area of Real Estate Property		698,000				197,000	197,000	123,000	123,000	238,000	51,000		1,500,000
Sales Price of Property Sold Discontinued Operations						25,000,000		19,700,000		53,500,000	8,300,000
Business Combination Purchase Price												215,000,000	348,000,000
Business Acquisition, Transaction Costs												328,000	385,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings												163,649,000
Business Acquisition Purchase Price Allocation Tangible Assets Tenant Improvements and FF and E												16,781,000
Business Acquisition Purchase Price Allocation Tangible Assets Accounts Receivable												1,014,000
Business Acquisition Purchase Price Allocation Tangible Assets Total												204,307,000
Business Acquisition Purchase Price Allocation Amortizable Intangible Assets Above Market Leases												632,000
Business Acquisition Purchase Price Allocation In-Place Leases												17,096,000
Business Acquisition Purchase Price Allocation Amortizable Intangible Liabilities Below Market Ground Lease												338,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill												18,066,000
Business Acquisition Purchase Price Allocation Tangible Liabilities Accounts Payable												(1,026,000)
Business Acquisitions Purchase Price Allocations Tangible Liabilities Total												(1,026,000)
Business Acquisition Purchase Price Allocation Amortizable Intangible Liabilities Below Market Lease												(9,374,000)
Business Acquisition Purchase Price Allocation Intangible Liabilities Total												(9,374,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net												$ 211,973,000