CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
Common Stock, Shares Outstanding, Beginning Balance at Dec. 31, 2019			17,363,000
Shareholders' Equity, Beginning Balance at Dec. 31, 2019	$ 503,492		$ 1,085	$ 123,281	$ 390,363		$ (11,237)	$ 0
Net income	11,901				11,901
Total other comprehensive income (loss), net of tax	12,166						12,166
Cash dividends declared	(8,913)				(8,913)
Share-based compensation	758			758
Exercise of stock options and issuance of other compensation-related equity awards, shares			14,000
Exercise of stock options and issuance of other compensation-related equity awards, value	(377)		$ 0	(872)				495
Treasury stock purchased under 2019 Stock Repurchase Program, shares acquired			(125,000)
Treasury stock purchased under 2019 Stock Repurchase Program, amount acquired	(4,322)							(4,322)
Common Stock, Shares Outstanding, Ending Balance at Mar. 31, 2020			17,252,000
Shareholders' Equity, Ending Balance at Mar. 31, 2020	$ 508,597		$ 1,085	123,167	387,243		929	(3,827)
Shareholders' Equity, Ending Balance (Accounting Standards Update 2016-13) at Mar. 31, 2020		$ (6,108)				$ (6,108)
Common Stock, Shares Outstanding, Beginning Balance at Dec. 31, 2020	17,265,337		17,265,000
Shareholders' Equity, Beginning Balance at Dec. 31, 2020	$ 534,195		$ 1,085	125,610	418,246		(7,391)	(3,355)
Net income	20,471				20,471
Total other comprehensive income (loss), net of tax	(12,615)						(12,615)
Cash dividends declared	(9,119)				(9,119)
Share-based compensation	918			918
Exercise of stock options and issuance of other compensation-related equity awards, shares			41,000
Exercise of stock options and issuance of other compensation-related equity awards, value	$ (251)		$ 0	(1,646)				1,395
Common Stock, Shares Outstanding, Ending Balance at Mar. 31, 2021	17,306,129		17,306,000
Shareholders' Equity, Ending Balance at Mar. 31, 2021	$ 533,599		$ 1,085	$ 124,882	$ 429,598		$ (20,006)	$ (1,960)