Income Taxes (Income Tax Expense Differed From Statutory Federal Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory federal tax rate	21.00%	21.00%	21.00%	35.00%
Tax exempt interest income	(2.00%)	(1.90%)	(2.60%)
Tax credits and adjustments	(3.40%)	(3.00%)	(0.30%)
Non-taxable earnings on company owned life insurance	(0.90%)	(0.60%)	(0.80%)
State taxes, net of federal tax benefit	1.10%	1.90%	1.50%
Nondeductible expenses	0.10%	0.20%	0.20%
Goodwill and contingent consideration adjustments			1.00%
Other, net	0.30%	0.20%	0.20%
Effective tax rate	16.20%	17.80%	20.20%