Non-controlling Interests (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Non-controlling Interests [Abstract]
Net income attributable to common shareholders		$ 37,044	$ 38,283	$ 188,722	$ 113,591
Increase in equity for conversion of operating partnership units				86	52
Decrease in additional paid-in capital for purchase of remaining non-controlling ownership interests in two consolidated joint ventures (1)	[1]			(9,480)	0
Change in common equity and net transfers from non-controlling interests				$ 179,328	$ 113,643

[1] Refer to Note 5, "Acquisitions, Dispositions, Assets Held for Sale and Impairment," for further discussion of acquisitions.