Noncontrolling Interests (Effect of Changes in Ownership Interest in Subsidiaries on Consolidated Equity)(Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Noncontrolling Interest [Abstract]
Net income adjusted for noncontrolling interests	$ 36,029	$ 35,396	$ 83,676	$ 98,699
Transfers from the noncontrolling interests:
Increase in equity for operating partnership units			111	0
Net increase in equity for the acquisition of noncontrolling interests			0	11,015
Change from net income adjusted for noncontrolling interests and transfers from the noncontrolling interests			$ 83,787	$ 109,714