Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts receivable	$ 5,295	$ 4,523
Accumulated amortization of acquired lease intangible assets	$ (45,639)	$ (36,112)
General partner units, outstanding	97,212,638	94,108,000
Limited Partners' Capital Account, Units Outstanding	154,170	154,170
Parent Company [Member]
Common Stock, Shares, Issued	97,212,638	94,108,061
Preferred stock, shares authorized	30,000,000	30,000,000
Preferred units of Series 3-5, units issued	13,000,000
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Exchangeable operating partnership units aggregate redemption value	$ 10,502	$ 9,833
Treasury stock, shares held at cost	417,862	425,246
Partnership Interest [Member]
Allowance for doubtful accounts receivable	$ 5,295	$ 4,523
Straight-line rent receivable allowance	1,365	652
Deferred costs accumulated amortization	88,694	81,822
Accumulated amortization of acquired lease intangible assets	45,639	36,112
Accumulated accretion of acquired lease intangible liabilities	$ 17,555	$ 13,993
Preferred stock, par value per share	$ 0.01	$ 0.01
Preferred units of Series 3-5, units issued	13,000,000	13,000,000
Preferred units of Series 3-5, units outstanding	13,000,000	13,000,000
Preferred stock, liquidation preferences per share	$ 25	$ 25
General partner units, outstanding	97,212,638	94,108,061
Limited Partners' Capital Account, Units Outstanding	154,170	154,170