Income Taxes (Schedule Of Company's Actual Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Computed “expected” tax expense	$ 152,751	$ 140,998	$ 128,438
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	(1,893)	(1,431)	(1,478)
Tax-exempt interest, net of cost to carry	(6,983)	(6,892)	(7,002)
Other Nontaxable or nondeductible items	5,105	4,043	4,292
Other	(2,732)	(2,444)	(2,349)
State and local income taxes, net of federal tax benefit	14,855	10,852	12,633
Changes in Unrecognized Tax Benefits	33	(37)	15
Total income tax expense	$ 161,136	$ 145,089	$ 134,549
Tax Jurisdiction of Domicile [Extensible Enumeration]	UNITED STATES
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	(0.26%)	(0.21%)	(0.24%)
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent	(0.96%)	(1.03%)	(1.15%)
Effective Income Tax Rate Reconciliation, Other nontaxable or nondeductible items, Percent	0.70%	0.60%	0.70%
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	(0.37%)	(0.36%)	(0.38%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	2.04%	1.62%	2.07%
Effective Income Tax Rate Reconciliation, Changes in Unrecognized Tax Benefits, Percent	0.00%	(0.01%)	0.00%
Effective Income Tax Rate Reconciliation, Percent	22.15%	21.61%	22.00%