Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	COMMON STOCK [Member]	CAPITAL SURPLUS [Member]	RETAINED EARNINGS [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) [Member]
Balance at beginning of period at Dec. 31, 2020		$ 32,720	$ 156,574	$ 871,161	$ 7,430
Shares issued for stock options		65	1,657
Shares acquired and canceled		(213)		(11,451)
Net income	$ 129,462			129,462
Dividends on common stock				(34,091)
Net cash settlement of options			(958)	(4,521)
Stock-based compensation arrangements			1,604
Net change	(2,565)				(2,565)
Balance at end of period at Sep. 30, 2021	1,146,874	32,572	158,877	950,560	4,865
Balance at beginning of period at Jun. 30, 2021		32,785	158,322	935,067	5,417
Shares acquired and canceled		(213)		(11,451)
Net income	38,750			38,750
Dividends on common stock				(11,806)
Stock-based compensation arrangements			555
Net change	(552)				(552)
Balance at end of period at Sep. 30, 2021	1,146,874	32,572	158,877	950,560	4,865
Balance at beginning of period at Dec. 31, 2021	1,171,734	32,603	159,914	977,067	2,150
Shares issued for stock options		253	6,758
Net income	135,974			135,974
Dividends on common stock				(36,725)
Stock-based compensation arrangements			1,545
Net change	(84,390)				(84,390)
Balance at end of period at Sep. 30, 2022	1,195,149	32,856	168,217	1,076,316	(82,240)
Balance at beginning of period at Jun. 30, 2022		32,781	165,295	1,034,107	(46,488)
Shares issued for stock options		75	2,295
Net income	55,352			55,352
Dividends on common stock				(13,143)
Stock-based compensation arrangements			627
Net change	(35,752)				(35,752)
Balance at end of period at Sep. 30, 2022	$ 1,195,149	$ 32,856	$ 168,217	$ 1,076,316	$ (82,240)