Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Capital Surplus	Accum.Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Balance at Beginning of Period at Dec. 31, 2021	$ 1,611,611	$ 180,000	$ 581	$ 602,508	$ (66,382)	$ 1,950,375	$ (1,055,471)
Beginning Balance (in shares) at Dec. 31, 2021		180,000	40,253,193
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	54,834					54,834
Other Comprehensive Income (Loss)	(179,771)				(179,771)
Share-Based Compensation	4,010			4,010
Common Stock Issued under Purchase and Equity Compensation Plans	2,395		$ 1	543		(185)	2,036
Common Stock Issued under Purchase and Equity Compensation Plans (in shares)			197,783
Common Stock Repurchased	(13,960)						(13,960)
Common Stock Repurchased (in shares)			(162,611)
Cash Dividends Declared Common Stock (per share)	(28,265)					(28,265)
Cash Dividends Declared Preferred Stock	(1,969)					(1,969)
Balance at End of Period at Mar. 31, 2022	1,448,885	$ 180,000	$ 582	607,061	(246,153)	1,974,790	(1,067,395)
Ending Balance (in shares) at Mar. 31, 2022		180,000	40,288,365
Balance at Beginning of Period at Dec. 31, 2021	1,611,611	$ 180,000	$ 581	602,508	(66,382)	1,950,375	(1,055,471)
Beginning Balance (in shares) at Dec. 31, 2021		180,000	40,253,193
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	164,497
Other Comprehensive Income (Loss)	(381,312)				(381,312)
Balance at End of Period at Sep. 30, 2022	1,282,384	$ 180,000	$ 582	615,985	(447,694)	2,024,641	(1,091,130)
Ending Balance (in shares) at Sep. 30, 2022		180,000	40,011,473
Balance at Beginning of Period at Mar. 31, 2022	1,448,885	$ 180,000	$ 582	607,061	(246,153)	1,974,790	(1,067,395)
Beginning Balance (in shares) at Mar. 31, 2022		180,000	40,288,365
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	56,862					56,862
Other Comprehensive Income (Loss)	(122,295)				(122,295)
Share-Based Compensation	4,162			4,162
Common Stock Issued under Purchase and Equity Compensation Plans	1,663			471		531	661
Common Stock Issued under Purchase and Equity Compensation Plans (in shares)			30,442
Common Stock Repurchased	(10,353)						(10,353)
Common Stock Repurchased (in shares)			(136,148)
Cash Dividends Declared Common Stock (per share)	(28,209)					(28,209)
Cash Dividends Declared Preferred Stock	(1,969)					(1,969)
Balance at End of Period at Jun. 30, 2022	1,348,746	$ 180,000	$ 582	611,694	(368,448)	2,002,005	(1,077,087)
Ending Balance (in shares) at Jun. 30, 2022		180,000	40,182,659
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	52,801					52,801
Other Comprehensive Income (Loss)	(79,246)				(79,246)
Share-Based Compensation	3,775			3,775
Common Stock Issued under Purchase and Equity Compensation Plans	1,617			516		(91)	1,192
Common Stock Issued under Purchase and Equity Compensation Plans (in shares)			19,741
Common Stock Repurchased	(15,235)						(15,235)
Common Stock Repurchased (in shares)			(190,927)
Cash Dividends Declared Common Stock (per share)	(28,105)					(28,105)
Cash Dividends Declared Preferred Stock	(1,969)					(1,969)
Balance at End of Period at Sep. 30, 2022	1,282,384	$ 180,000	$ 582	615,985	(447,694)	2,024,641	(1,091,130)
Ending Balance (in shares) at Sep. 30, 2022		180,000	40,011,473
Balance at Beginning of Period at Dec. 31, 2022	1,316,995	$ 180,000	$ 582	620,578	(434,658)	2,055,912	(1,105,419)
Beginning Balance (in shares) at Dec. 31, 2022		180,000	39,835,750
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	46,842					46,842
Other Comprehensive Income (Loss)	29,360				29,360
Share-Based Compensation	3,371			3,371
Common Stock Issued under Purchase and Equity Compensation Plans	1,568		$ 1	177		1,587	(197)
Common Stock Issued under Purchase and Equity Compensation Plans (in shares)			13,164
Common Stock Repurchased	(13,793)						(13,793)
Common Stock Repurchased (in shares)			(202,408)
Cash Dividends Declared Common Stock (per share)	(27,944)					(27,944)
Cash Dividends Declared Preferred Stock	(1,969)					(1,969)
Balance at End of Period at Mar. 31, 2023	1,354,430	$ 180,000	$ 583	624,126	(405,298)	2,074,428	(1,119,409)
Ending Balance (in shares) at Mar. 31, 2023		180,000	39,646,506
Balance at Beginning of Period at Dec. 31, 2022	1,316,995	$ 180,000	$ 582	620,578	(434,658)	2,055,912	(1,105,419)
Beginning Balance (in shares) at Dec. 31, 2022		180,000	39,835,750
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	140,806
Other Comprehensive Income (Loss)	(6,953)				(6,953)
Balance at End of Period at Sep. 30, 2023	1,363,840	$ 180,000	$ 583	632,425	(441,611)	2,108,702	(1,116,259)
Ending Balance (in shares) at Sep. 30, 2023		180,000	39,748,700
Balance at Beginning of Period at Mar. 31, 2023	1,354,430	$ 180,000	$ 583	624,126	(405,298)	2,074,428	(1,119,409)
Beginning Balance (in shares) at Mar. 31, 2023		180,000	39,646,506
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	46,061					46,061
Other Comprehensive Income (Loss)	(18,133)				(18,133)
Share-Based Compensation	4,301			4,301
Common Stock Issued under Purchase and Equity Compensation Plans	1,657			(225)		699	1,183
Common Stock Issued under Purchase and Equity Compensation Plans (in shares)			81,601
Common Stock Repurchased	(138)						(138)
Common Stock Repurchased (in shares)			(2,759)
Cash Dividends Declared Common Stock (per share)	(27,930)					(27,930)
Cash Dividends Declared Preferred Stock	(1,969)					(1,969)
Balance at End of Period at Jun. 30, 2023	1,358,279	$ 180,000	$ 583	628,202	(423,431)	2,091,289	(1,118,364)
Ending Balance (in shares) at Jun. 30, 2023		180,000	39,725,348
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	47,903					47,903
Other Comprehensive Income (Loss)	(18,180)				(18,180)
Share-Based Compensation	4,307			4,307
Common Stock Issued under Purchase and Equity Compensation Plans	1,575			(84)		(571)	2,230
Common Stock Issued under Purchase and Equity Compensation Plans (in shares)			26,275
Common Stock Repurchased	(125)						(125)
Common Stock Repurchased (in shares)			(2,923)
Cash Dividends Declared Common Stock (per share)	(27,950)					(27,950)
Cash Dividends Declared Preferred Stock	(1,969)					(1,969)
Balance at End of Period at Sep. 30, 2023	$ 1,363,840	$ 180,000	$ 583	$ 632,425	$ (441,611)	$ 2,108,702	$ (1,116,259)
Ending Balance (in shares) at Sep. 30, 2023		180,000	39,748,700