Real Estate And Accumulated Depreciation (Changes In Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance at beginning of year	$ 1,087,642	$ 1,028,619	$ 1,058,040
Additions at cost	131,120	120,426	125,226
Retirements or sales	(33,132)	(42,603)	(148,882)
Property held for sale	(1,084)	(18,800)	(5,765)
Balance at end of year	$ 1,184,546	$ 1,087,642	$ 1,028,619