Consolidated Statements of Shareholders’ Equity (unaudited) - USD ($) $ in Thousands	Total	Cumulative effect of change in accounting principle for ASU 2022-02	Common Stock	Capital Surplus	Retained Earnings	Retained Earnings Cumulative effect of change in accounting principle for ASU 2022-02	Accumulated Other Comprehensive Income (Loss), Net of Tax	Treasury Stock
Balance at beginning of period (in shares) at Dec. 31, 2021			72,017,126
Balance at beginning of period (in shares) at Dec. 31, 2021								2,407,898
Balance at beginning of period at Dec. 31, 2021	$ 2,966,451		$ 72,017	$ 1,924,813	$ 1,006,436		$ 15,590	$ (52,405)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			164,346
Issuance of restricted shares	1,341		$ 164	1,177
Forfeitures of restricted shares (in shares)			(10,751)
Forfeitures of restricted shares	(91)		$ (10)	(81)
Proceeds from exercise of stock options (in shares)			81,135
Proceeds from exercise of stock options	2,324		$ 80	2,244
Share-based compensation	2,935			2,935
Purchase of treasury shares (in shares)								483,497
Purchase of treasury shares	(22,282)							$ (22,282)
Net income	171,764				171,764
Dividends on common shares	(20,841)				(20,841)
Other comprehensive loss during the period	(28,225)						(28,225)
Balance at end of period (in shares) at Jun. 30, 2022			72,251,856
Balance at end of period (in shares) at Jun. 30, 2022								2,891,395
Balance at end of period at Jun. 30, 2022	3,073,376		$ 72,251	1,931,088	1,157,359		(12,635)	$ (74,687)
Balance at beginning of period (in shares) at Dec. 31, 2021			72,017,126
Balance at beginning of period (in shares) at Dec. 31, 2021								2,407,898
Balance at beginning of period at Dec. 31, 2021	$ 2,966,451		$ 72,017	1,924,813	1,006,436		15,590	$ (52,405)
Balance at end of period (in shares) at Dec. 31, 2022			72,263,727
Balance at end of period (in shares) at Dec. 31, 2022	2,894,677							2,894,677
Balance at end of period at Dec. 31, 2022	$ 3,197,400	$ 1,277	$ 72,264	1,935,211	1,311,258	$ 1,277	(46,507)	$ (74,826)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	Accounting Standards Update 2016-02 [Member]
Balance at beginning of period (in shares) at Mar. 31, 2022			72,212,322
Balance at beginning of period (in shares) at Mar. 31, 2022								2,773,238
Balance at beginning of period at Mar. 31, 2022	$ 3,007,159		$ 72,212	1,928,702	1,077,725		(1,841)	$ (69,639)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			18,953
Issuance of restricted shares	0		$ 19	(19)
Forfeitures of restricted shares (in shares)			(10,751)
Forfeitures of restricted shares	(92)		$ (11)	(81)
Proceeds from exercise of stock options (in shares)			31,332
Proceeds from exercise of stock options	880		$ 31	849
Share-based compensation	1,637			1,637
Purchase of treasury shares (in shares)								118,157
Purchase of treasury shares	(5,048)							$ (5,048)
Net income	90,066				90,066
Dividends on common shares	(10,432)				(10,432)
Other comprehensive loss during the period	(10,794)						(10,794)
Balance at end of period (in shares) at Jun. 30, 2022			72,251,856
Balance at end of period (in shares) at Jun. 30, 2022								2,891,395
Balance at end of period at Jun. 30, 2022	$ 3,073,376		$ 72,251	1,931,088	1,157,359		(12,635)	$ (74,687)
Balance at beginning of period (in shares) at Dec. 31, 2022			72,263,727
Balance at beginning of period (in shares) at Dec. 31, 2022	2,894,677							2,894,677
Balance at beginning of period at Dec. 31, 2022	$ 3,197,400	$ 1,277	$ 72,264	1,935,211	1,311,258	$ 1,277	(46,507)	$ (74,826)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			131,930
Issuance of restricted shares	0		$ 132	(132)
Issuance of common shares pursuant to PSU agreements (in shares)			102,973
Issuance of common shares pursuant to PSU agreements	0		$ 103	(103)
Proceeds from exercise of stock options (in shares)			16,000
Proceeds from exercise of stock options	476		$ 16	460
Share-based compensation	4,429			4,429
Purchase of treasury shares (in shares)								480,170
Purchase of treasury shares	(17,048)							$ (17,048)
Net income	123,056				123,056
Dividends on common shares	(20,849)				(20,849)
Other comprehensive loss during the period	$ (4,111)						(4,111)
Balance at end of period (in shares) at Jun. 30, 2023			72,514,630
Balance at end of period (in shares) at Jun. 30, 2023	3,374,847							3,374,847
Balance at end of period at Jun. 30, 2023	$ 3,284,630		$ 72,515	1,939,865	1,414,742		(50,618)	$ (91,874)
Balance at beginning of period (in shares) at Mar. 31, 2023			72,484,210
Balance at beginning of period (in shares) at Mar. 31, 2023								3,110,347
Balance at beginning of period at Mar. 31, 2023	3,253,195		$ 72,484	1,937,664	1,362,512		(35,581)	$ (83,884)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			30,420
Issuance of restricted shares	0		$ 31	(31)
Share-based compensation	2,232			2,232
Purchase of treasury shares (in shares)								264,500
Purchase of treasury shares	(7,990)							$ (7,990)
Net income	62,635				62,635
Dividends on common shares	(10,405)				(10,405)
Other comprehensive loss during the period	$ (15,037)						(15,037)
Balance at end of period (in shares) at Jun. 30, 2023			72,514,630
Balance at end of period (in shares) at Jun. 30, 2023	3,374,847							3,374,847
Balance at end of period at Jun. 30, 2023	$ 3,284,630		$ 72,515	$ 1,939,865	$ 1,414,742		$ (50,618)	$ (91,874)