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		51	1,258
Net income	$ 42,520			42,520
Dividends on common stock				(11,134)
Net cash settlement of options			(958)	(4,521)
Stock-based compensation arrangements			576
Net change	(1,006)				(1,006)
Balance at end of period at Mar. 31, 2021	1,094,671	32,771	157,450	898,026	6,424
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		123	3,020
Net income	35,915			35,915
Dividends on common stock				(11,782)
Stock-based compensation arrangements			458
Net change	(31,666)				(31,666)
Balance at end of period at Mar. 31, 2022	$ 1,167,802	$ 32,726	$ 163,392	$ 1,001,200	$ 29,516