CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (in shares) at Dec. 31, 2019		15,144,719
Beginning Balance at Dec. 31, 2019	$ 473,415	$ 139,103	$ 340,580	$ (6,268)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	24,433		24,433
Other comprehensive income, net of tax	25,624			25,624
Stock-based compensation expense	951	$ 951
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit (shares)		35,353
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings	(100)	$ (100)
Common stock repurchased (in shares)		(217,031)
Common stock repurchased	(7,973)	$ (7,973)
Cash dividends declared	(9,883)		(9,883)
Ending Balance (in shares) at Jun. 30, 2020		14,963,041
Ending Balance at Jun. 30, 2020	506,467	$ 131,981	355,130	19,356
Beginning Balance (in shares) at Mar. 31, 2020		14,951,597
Beginning Balance at Mar. 31, 2020	492,680	$ 131,498	349,141	12,041
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	10,940		10,940
Other comprehensive income, net of tax	7,315			7,315
Stock-based compensation expense	530	$ 530
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit (shares)		11,444
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings	(47)	$ (47)
Cash dividends declared	(4,951)		(4,951)
Ending Balance (in shares) at Jun. 30, 2020		14,963,041
Ending Balance at Jun. 30, 2020	506,467	$ 131,981	355,130	19,356
Beginning Balance (in shares) at Dec. 31, 2020		14,909,097
Beginning Balance at Dec. 31, 2020	529,314	$ 131,072	377,502	20,740
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	37,883		37,883
Other comprehensive income, net of tax	(12,072)			(12,072)
Stock-based compensation expense	1,514	$ 1,514
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit (shares)		41,970
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings	(308)	$ (308)
Cash dividends declared	(10,783)		(10,783)
Ending Balance (in shares) at Jun. 30, 2021		14,951,067
Ending Balance at Jun. 30, 2021	545,548	$ 132,278	404,602	8,668
Beginning Balance (in shares) at Mar. 31, 2021		14,928,434
Beginning Balance at Mar. 31, 2021	532,120	$ 131,695	391,860	8,565
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	18,143		18,143
Other comprehensive income, net of tax	103			103
Stock-based compensation expense	811	$ 811
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit (shares)		22,633
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings	(228)	$ (228)
Cash dividends declared	(5,401)		(5,401)
Ending Balance (in shares) at Jun. 30, 2021		14,951,067
Ending Balance at Jun. 30, 2021	$ 545,548	$ 132,278	$ 404,602	$ 8,668