Earnings Per Common Share (Computation Of Basic And Diluted Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net income	$ 78,591	$ 91,157	$ 88,354	$ 108,066	$ 116,143	$ 107,737	$ 169,748	$ 223,880
Weighted average number of common shares outstanding - basic (in shares)	217,030				220,593		216,906	220,481
Effect of potentially dilutive common shares (in shares)	249				429		427	447
Weighted average number of shares outstanding, diluted (in shares)	217,279				221,022		217,333	220,928
Earnings per common share:
Basic (in dollars per share)	$ 0.36				$ 0.53		$ 0.78	$ 1.02
Diluted (in dollars per share)	$ 0.36				$ 0.53		$ 0.78	$ 1.01