CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance at Dec. 31, 2019	$ 15,828	$ 274,785	$ 245,836	$ (1,098)	$ 535,351
Net income			11,228		11,228
Other comprehensive income (loss), net of tax				(3,691)	(3,691)
Repurchase and cancellation of shares of common stock as a result of share repurchase program	(101)	(1,844)	(1,835)		(3,780)
Common cash dividends declared			(942)		(942)
Stock-based compensation expense		641			641
Issuance of common stock under employee benefit plans	47	285			332
Balance at Mar. 31, 2020	15,774	273,867	254,287	(4,789)	539,139
Impact of adoption of ASU 2016-01					300,804
Balance at Dec. 31, 2020	15,806	275,807	300,804	1,376	593,793
Net income			17,982		17,982
Other comprehensive income (loss), net of tax				(1,751)	(1,751)
Common cash dividends declared			(949)		(949)
Stock-based compensation expense		841			841
Issuance of common stock under employee benefit plans	(38)	298			260
Balance at Mar. 31, 2021	$ 15,844	$ 276,350	316,900	$ (375)	608,719
Impact of adoption of ASU 2016-01 | Accounting Standards Update 2016-13			$ 937		937
Impact of adoption of ASU 2016-01					$ 316,900