Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Stock dividend, percent		300.00%	[1]	300.00%	300.00%
Stock dividends (in shares)		588,025	[1]	570,884	554,264
Cash Dividends Paid (in dollars per share)	[2]	$ 1.02		$ 0.99	$ 0.94
Shares Issued for Stock Option Exercises (in shares		33,895
Shares Issued for Stock Option Exercises, net (in shares)		33,112		84,216	105,055
Shares Issued Under Directors Stock Plan (in shares)		4,245		7,580	5,601
Shares Issued Under the Employee Stock Purchase Plan (in shares)		18,286		15,379	14,832
Shares Issued for Dividend Reinvestment Plans (in shares)		63,425		51,191	49,714
Purchase of Treasury Stock (in shares)		52,505		73,495	58,527
Allocation of ESOP Stock (in shares)				5,151	4,931
Treasury Stock, Shares (in shares)		4,678,736		4,608,258

[1] Included in the shares issued for the 3% stock dividend in 2020 were treasury shares of 137,041

[2] Cash dividends paid per share have been adjusted for the September 25, 2020 3% stock dividend.