Non-controlling Interests (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Non-controlling Interests [Abstract]
Net income attributable to common shareholders	$ 41,730	$ 115,599
Increase in equity for conversion of operating partnership units	134	16
Decrease in additional paid-in capital for purchase of remaining non-controlling ownership interests in two consolidated joint ventures	0	(9,480)
Change in common equity and net transfers from non-controlling interests	$ 41,864	$ 106,135