Noncontrolling Interests (Effect Of Changes In Ownership Interest In Subsidiaries On Consolidated Equity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net Income Adjusted for Noncontrolling Interests	$ 335,274	$ 238,933	$ 174,352
Transfers from the noncontrolling interests:
Increase in equity for operating partnership units	0	0	111
Net increase in equity for the acquisition of noncontrolling interests	0	2,139	0
Change from net income adjusted for noncontrolling interests and transfers from the noncontrolling interests	$ 335,274	$ 241,072	$ 174,463