Per Share Data (Calculation Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Number of common share equivalent securities excluded from the diluted earnings per share calculation	1,700	2,000	1,800	2,000
Income from continuing operations attributable to common shareholders	$ 29,483	$ 34,957	$ 91,009	$ 94,718
Amount allocated to participating securities	(30)	(74)	(122)	(204)
Net income attributable to common shareholders – basic	$ 29,453	$ 34,883	$ 90,887	$ 94,514
Total earnings per common share – basic	$ 0.29	$ 0.35	$ 0.90	$ 0.95
Net income attributable to common shareholders – diluted	$ 29,453	$ 34,883	$ 90,887	$ 94,514
Total earnings per common share – diluted	$ 0.29	$ 0.35	$ 0.90	$ 0.95
Weighted average number of common shares outstanding – basic	103,071	99,419	101,119	99,372
Common share options and share awards granted	100	36	80	42
Weighted average number of common shares outstanding – diluted	103,171	99,455	101,199	99,414