Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Capital Surplus	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss), Net of Tax	Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting for credit losses		$ (56,704)				$ (56,704)
Balance at beginning of period (in shares) at Dec. 31, 2019			71,499,829
Balance at beginning of period at Dec. 31, 2019	$ 2,469,582		$ 71,500	$ 1,907,108	$ 507,950		$ 17,995	$ (34,971)
Balance at beginning of period (in shares) at Dec. 31, 2019								1,995,996
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			164,476
Issuance of restricted shares	289		$ 164	125
Forfeitures of restricted shares (in shares)			(12,250)
Forfeitures of restricted shares	(221)		$ (12)	(209)
Exercise of stock options (in shares)			101,650
Exercise of stock options	2,262		$ 102	2,160
Share-based compensation	4,101			4,101
Purchase of treasury shares (in shares)								216,228
Purchase of treasury shares	(7,995)							$ (7,995)
Net income	261,988				261,988
Dividends on common shares	(41,724)				(41,724)
Other comprehensive income (loss) during the period	15,510						15,510
Balance at end of period (in shares) at Dec. 31, 2020			71,753,705
Balance at end of period at Dec. 31, 2020	2,647,088		$ 71,754	1,913,285	671,510		33,505	$ (42,966)
Balance at end of period (in shares) at Dec. 31, 2020								2,212,224
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			99,308
Issuance of restricted shares	599		$ 99	500
Forfeitures of restricted shares (in shares)			(2,695)
Forfeitures of restricted shares	(53)		$ (3)	(50)
Exercise of stock options (in shares)			166,808
Exercise of stock options	4,532		$ 167	4,365
Share-based compensation	6,713			6,713
Purchase of treasury shares (in shares)								195,674
Purchase of treasury shares	(9,439)							$ (9,439)
Net income	376,913				376,913
Dividends on common shares	(41,987)				(41,987)
Other comprehensive income (loss) during the period	(17,915)						(17,915)
Balance at end of period (in shares) at Dec. 31, 2021			72,017,126
Balance at end 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, 2021	2,407,898							2,407,898
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted shares (in shares)			165,687
Issuance of restricted shares	$ 1,341		$ 166	1,175
Forfeitures of restricted shares (in shares)			(14,889)
Forfeitures of restricted shares	(143)		$ (15)	(128)
Exercise of stock options (in shares)			95,803
Exercise of stock options	2,799		$ 96	2,703
Share-based compensation	6,648			6,648
Purchase of treasury shares (in shares)								486,779
Purchase of treasury shares	(22,421)							$ (22,421)
Net income	346,540				346,540
Dividends on common shares	(41,718)				(41,718)
Other comprehensive income (loss) during the period	(62,097)						(62,097)
Balance at end of period (in shares) at Dec. 31, 2022			72,263,727
Balance at end of period at Dec. 31, 2022	$ 3,197,400		$ 72,264	$ 1,935,211	$ 1,311,258		$ (46,507)	$ (74,826)
Balance at end of period (in shares) at Dec. 31, 2022	2,894,677							2,894,677