Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Parent Company [Member]
Deferred costs accumulated amortization	$ 102,141	$ 101,093
Accumulated amortization of acquired lease intangible assets	225,693	219,689
Accumulated accretion of acquired lease intangible liabilities	$ 99,163	$ 92,746
Preferred stock, par value per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	30,000,000	30,000,000
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	220,000,000	220,000,000
Common stock, shares issued	167,517,243	167,904,593
Exchangeable operating partnership units aggregate redemption value	$ 23,615	$ 20,532
Treasury stock, shares held at cost	410,963	390,163
Restricted Cash and Cash Equivalents	$ 3,305	$ 2,658
Partnership Interest [Member]
Deferred costs accumulated amortization	102,141	101,093
Accumulated amortization of acquired lease intangible assets	225,693	219,689
Accumulated accretion of acquired lease intangible liabilities	$ 99,163	$ 92,746
Preferred units of general partner par value per unit	$ 0.01	$ 0.01
General partner units, outstanding	167,517,243	167,904,593
Limited partner units, outstanding	349,902	349,902
Restricted Cash and Cash Equivalents	$ 3,305	$ 2,658