Common Share Capitalization (Summary Of Common Shares Outstanding) (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Shares Outstanding, period begin	31,335,938	32,294,703
Shares repurchased	(943,897)	(130,488)
Director LTIP Units exercised	0	0
Common Shares Outstanding, period end	30,392,041	32,164,215