CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Treasury Stock (at cost) [Member]	Accumulated Other Comprehensive Loss, net of tax [Member]
Balance at beginning of year at Dec. 31, 2021			$ 972,547	$ 1,427,295		$ (236,442)	$ (83,999)
Balance at beginning of year (ASU 2022-02 [Member]) at Dec. 31, 2021					$ 0
Stock-based compensation expense			5,407
Common stock repurchases (See Note 15)						(277,769)
Common stock reissued under stock-based compensation plan			(7,365)			7,365
Restricted stock forfeited			133			(133)
Net income	$ 305,072			305,072
Dividends on common stock (2024 - $0.64 per share; 2023 - $0.56 per share; 2022 - $0.46 per share)				(88,158)
Other comprehensive income (loss), net of tax	(720,779)						(720,779)
Balance at end of year at Dec. 31, 2022	1,325,540	$ 22,366	970,722	1,644,209		(506,979)	(804,778)
Balance at end of year (ASU 2022-02 [Member]) at Dec. 31, 2022					(1,357)
Stock-based compensation expense			7,799
Common stock repurchases (See Note 15)						(203,241)
Common stock reissued under stock-based compensation plan			(13,531)			13,531
Restricted stock forfeited			717			(717)
Net income	302,864			302,864
Dividends on common stock (2024 - $0.64 per share; 2023 - $0.56 per share; 2022 - $0.46 per share)				(99,604)
Other comprehensive income (loss), net of tax	165,608						165,608
Balance at end of year at Dec. 31, 2023	1,497,609	22,366	965,707	1,846,112		(697,406)	(639,170)
Balance at end of year (ASU 2022-02 [Member]) at Dec. 31, 2023					$ 0
Stock-based compensation expense			8,706
Common stock repurchases (See Note 15)						(102,393)
Common stock reissued under stock-based compensation plan			(9,659)			9,659
Restricted stock forfeited			210			(210)
Net income	298,724			298,724
Dividends on common stock (2024 - $0.64 per share; 2023 - $0.56 per share; 2022 - $0.46 per share)				(106,024)
Other comprehensive income (loss), net of tax	72,614						72,614
Balance at end of year at Dec. 31, 2024	$ 1,669,236	$ 22,366	$ 964,964	$ 2,038,812		$ (790,350)	$ (566,556)