Summary of Significant Accounting Policies (Schedule Of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Net income	$ 259,052	$ 169,078	$ 166,944
Weighted average common shares outstanding	67,434	69,018	69,567
Dilutive effect of stock-based awards	421	409	459
Shares used in computing diluted earnings per share	67,855	69,427	70,026
Basic earnings per share	$ 3.84	$ 2.45	$ 2.40
Diluted earnings per share	$ 3.82	$ 2.44	$ 2.38
Number of antidilutive options that were excluded from computation of earnings per share	0	0	0