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 Loss, Net of Tax	Treasury Stock
Balance at beginning of period (in shares) at Dec. 31, 2022			72,263,727
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)
Balance at beginning of period (in shares) at Dec. 31, 2022								2,894,677
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 income (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 at Jun. 30, 2023	3,284,630		$ 72,515	1,939,865	1,414,742		(50,618)	$ (91,874)
Balance at end of period (in shares) at Jun. 30, 2023								3,374,847
Balance at beginning of period (in shares) at Mar. 31, 2023			72,484,210
Balance at beginning of period at Mar. 31, 2023	3,253,195		$ 72,484	1,937,664	1,362,512		(35,581)	$ (83,884)
Balance at beginning of period (in shares) at Mar. 31, 2023								3,110,347
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 income (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 at Jun. 30, 2023	$ 3,284,630		$ 72,515	1,939,865	1,414,742		(50,618)	$ (91,874)
Balance at end of period (in shares) at Jun. 30, 2023								3,374,847
Balance at beginning of period (in shares) at Dec. 31, 2023	72,516,079		72,516,079
Balance at beginning of period at Dec. 31, 2023	$ 3,426,747		$ 72,516	1,945,385	1,539,957		(35,939)	$ (95,172)
Balance at beginning of period (in shares) at Dec. 31, 2023	3,462,738							3,462,738
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			125,832
Issuance of restricted shares	$ 0		$ 126	(126)
Issuance of common shares pursuant to PSU agreements (in shares)			63,301
Issuance of common shares pursuant to PSU agreements	0		$ 63	(63)
Forfeitures of restricted shares (in shares)			(8,003)
Forfeitures of restricted shares	(181)		$ (8)	(173)
Share-based compensation	5,823			5,823
Purchase of treasury shares (in shares)								167,898
Purchase of treasury shares	(7,955)							$ (7,955)
Net income	165,097				165,097
Dividends on common shares	(20,836)				(20,836)
Other comprehensive income (loss) during the period	$ (2,081)						(2,081)
Balance at end of period (in shares) at Jun. 30, 2024	72,697,209		72,697,209
Balance at end of period at Jun. 30, 2024	$ 3,566,614		$ 72,697	1,950,846	1,684,218		(38,020)	$ (103,127)
Balance at end of period (in shares) at Jun. 30, 2024	3,630,636							3,630,636
Balance at beginning of period (in shares) at Mar. 31, 2024			72,683,199
Balance at beginning of period at Mar. 31, 2024	$ 3,484,738		$ 72,683	1,948,352	1,603,832		(39,959)	$ (100,170)
Balance at beginning of period (in shares) at Mar. 31, 2024								3,567,936
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			22,013
Issuance of restricted shares	0		$ 22	(22)
Forfeitures of restricted shares (in shares)			(8,003)
Forfeitures of restricted shares	(181)		$ (8)	(173)
Share-based compensation	2,689			2,689
Purchase of treasury shares (in shares)								62,700
Purchase of treasury shares	(2,957)							$ (2,957)
Net income	90,785				90,785
Dividends on common shares	(10,399)				(10,399)
Other comprehensive income (loss) during the period	$ 1,939						1,939
Balance at end of period (in shares) at Jun. 30, 2024	72,697,209		72,697,209
Balance at end of period at Jun. 30, 2024	$ 3,566,614		$ 72,697	$ 1,950,846	$ 1,684,218		$ (38,020)	$ (103,127)
Balance at end of period (in shares) at Jun. 30, 2024	3,630,636							3,630,636