CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2019	$ 18,036	$ 140,492	$ 146,696	$ 958	$ 306,182
Balance (in shares) at Dec. 31, 2019	18,036,115
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	29,429	0	29,429
Cash dividends declared	0	0	(1,624)	0	(1,624)
Other comprehensive income (loss), net of tax	0	0	0	17,805	17,805
Exercise of employee stock options and vesting of restricted stock units	$ 28	(157)	0	0	(129)
Exercise of employee stock options and vesting of restricted stock units (in shares)	27,759
Repurchases of common stock	$ (5)	(56)	0	0	(61)
Repurchases of common stock (in shares)	(4,700)
Stock based compensation	$ 0	966	0	0	966
Balance at Sep. 30, 2020	$ 18,059	141,245	174,501	18,763	352,568
Balance (in shares) at Sep. 30, 2020	18,059,174
Balance at Jun. 30, 2020	$ 18,059	140,620	158,311	19,544	336,534
Balance (in shares) at Jun. 30, 2020	18,059,174
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	16,731	0	16,731
Cash dividends declared	0	0	(541)	0	(541)
Other comprehensive income (loss), net of tax	0	0	0	(781)	(781)
Repurchases of common stock	$ 0	0	0	0	0
Repurchases of common stock (in shares)	0
Stock based compensation	$ 0	625	0	0	625
Balance at Sep. 30, 2020	$ 18,059	141,245	174,501	18,763	352,568
Balance (in shares) at Sep. 30, 2020	18,059,174
Balance at Dec. 31, 2020	$ 18,076	141,112	189,521	21,339	$ 370,048
Balance (in shares) at Dec. 31, 2020	18,076,364				18,076,364
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	44,000	0	$ 44,000
Cash dividends declared	0	0	(3,784)	0	(3,784)
Other comprehensive income (loss), net of tax	0	0	0	(7,025)	(7,025)
Exercise of employee stock options and vesting of restricted stock units	$ 21	(127)	0	0	(106)
Exercise of employee stock options and vesting of restricted stock units (in shares)	20,552
Repurchases of common stock	$ (273)	(5,809)	0	0	(6,082)
Repurchases of common stock (in shares)	(272,822)
Stock based compensation	$ 0	1,225	0	0	1,225
Balance at Sep. 30, 2021	$ 17,824	136,401	229,737	14,314	$ 398,276
Balance (in shares) at Sep. 30, 2021	17,824,094				17,824,094
Balance at Jun. 30, 2021	$ 18,014	140,212	216,164	18,425	$ 392,815
Balance (in shares) at Jun. 30, 2021	18,014,398
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	15,190	0	15,190
Cash dividends declared	0	0	(1,617)	0	(1,617)
Other comprehensive income (loss), net of tax	0	0	0	(4,111)	(4,111)
Repurchases of common stock	$ (190)	(4,214)	0	0	(4,404)
Repurchases of common stock (in shares)	(190,304)
Stock based compensation	$ 0	403	0	0	403
Balance at Sep. 30, 2021	$ 17,824	$ 136,401	$ 229,737	$ 14,314	$ 398,276
Balance (in shares) at Sep. 30, 2021	17,824,094				17,824,094