Consolidated Condensed Statements Of Changes In Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock At Cost [Member]	Accumulated Other Comprehensive Income (loss) [Member]
Balance at Dec. 31, 2019				$ 0	$ 459,389	$ 646,847			$ (127,633)	$ (9,589)
Net Income	$ 22,372					22,372
Other comprehensive income (loss)	17,693									17,693
Dividends on common shares						(20,111)
Cash payment for fractional shares in dividend reinvestment plan					(1)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures					(3,865)	(528)			(2,500)
Treasury Stock, Value, Acquired, Cost Method									7,507
Share-based Payment Arrangement, Expense	$ 1,300				$ 1,254
Common Stock, Dividends, Per Share, Cash Paid	$ 1.22
Stock Issued During Period, Shares, Restricted Stock Award, Gross	25,028
Stock issued during period, shares, withheld for tax, tax restricted stock	11,646
Treasury Stock, Shares, Acquired	76,000				76,000
Balance at Mar. 31, 2020				0	$ 456,777	649,636			(132,640)	8,104
Balance at Dec. 31, 2020	$ 1,040,256	$ (7,956)	$ 1,032,300	0	460,687	704,764			(130,766)	5,571
Balance (Accounting Standards Update 2016-13) at Dec. 31, 2020							$ (7,956)	$ 696,808
Net Income	42,831					42,831
Other comprehensive income (loss)	(13,472)									(13,472)
Dividends on common shares						(20,365)
Cash payment for fractional shares in dividend reinvestment plan					(1)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures					(3,988)	(44)			(2,174)
Share-based Payment Arrangement, Expense	$ 1,800				$ 1,836
Common Stock, Dividends, Per Share, Cash Paid	$ 1.23
Stock Issued During Period, Shares, Restricted Stock Award, Gross	21,764
Stock issued during period, shares, withheld for tax, tax restricted stock	14,108
Treasury Stock, Shares, Acquired					0
Balance at Mar. 31, 2021	$ 1,041,271			$ 0	$ 458,534	$ 719,230			$ (128,592)	$ (7,901)