Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Deferred Compensation, Share-Based Payments [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2020	26,807
Balance at Dec. 31, 2020	$ 466,006	$ 35	$ 114,412	$ 264,356	$ 844,809
Net income				64,789	64,789
Other comprehensive income (loss)			(43,128)		(43,128)
Exercise of stock options (in shares)	53
Exercise of stock options	$ 3,017				3,017
Stock based compensation	1,100				1,100
Stock awarded to employees	93				93
Dividends				(33,021)	(33,021)
Restricted stock activity (in shares)	9
Restricted stock activity	$ 526				526
Retirement of common stock (in shares)	(4)
Retirement of common stock	$ (66)			(166)	(232)
Balance (in shares) at Sep. 30, 2021	26,866
Balance at Sep. 30, 2021	$ 470,676	35	71,284	295,958	837,953
Balance (in shares) at Jun. 30, 2021	26,865
Balance at Jun. 30, 2021	$ 470,330	35	86,921	284,910	842,196
Net income				22,063	22,063
Other comprehensive income (loss)			(15,637)		(15,637)
Exercise of stock options (in shares)	0
Exercise of stock options	$ 0				0
Stock based compensation	324				324
Stock awarded to employees	22				22
Dividends				(11,015)	(11,015)
Balance (in shares) at Sep. 30, 2021	26,866
Balance at Sep. 30, 2021	$ 470,676	35	71,284	295,958	837,953
Balance (in shares) at Dec. 31, 2021	26,866
Balance at Dec. 31, 2021	$ 471,008	35	49,664	306,395	827,102
Net income				82,690	82,690
Other comprehensive income (loss)			(340,461)		(340,461)
Exercise of stock options (in shares)	39
Exercise of stock options	$ 2,171				2,171
Stock based compensation	$ 1,017				1,017
Stock awarded to employees (in shares)	1
Stock awarded to employees	$ 74				74
Dividends				(33,879)	(33,879)
Restricted stock activity (in shares)	8
Restricted stock activity	$ 492				492
Retirement of common stock (in shares)	(3)
Retirement of common stock	$ (65)			(153)	(218)
Balance (in shares) at Sep. 30, 2022	26,911
Balance at Sep. 30, 2022	$ 474,697	35	(290,797)	355,053	538,988
Balance (in shares) at Jun. 30, 2022	26,896
Balance at Jun. 30, 2022	$ 473,520	35	(188,025)	331,596	617,126
Net income				34,760	34,760
Other comprehensive income (loss)			(102,772)		(102,772)
Exercise of stock options (in shares)	15
Exercise of stock options	$ 816				816
Stock based compensation	$ 339				339
Stock awarded to employees (in shares)	0
Stock awarded to employees	$ 22				22
Dividends				(11,303)	(11,303)
Balance (in shares) at Sep. 30, 2022	26,911
Balance at Sep. 30, 2022	$ 474,697	$ 35	$ (290,797)	$ 355,053	$ 538,988