Summary Of Significant Accounting Policies (Net Income Per Common Share) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Abstract]
Basic weighted average common shares outstanding	174,287	173,969	173,613
Net effect of dilutive stock options - based on treasury stock method	243	328	538
Diluted weighted average common shares outstanding	174,530	174,297	174,151