Common Share Capitalization (Summary Of Common Shares Outstanding) (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Shares Outstanding, period begin	32,164,215	32,962,979	32,294,703	33,126,012
Shares repurchased	(51,518)	(219,623)	(182,006)	(382,656)
Common Shares Outstanding, period end	32,112,697	32,743,356	32,112,697	32,743,356