Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2020	$ 1,741,117	$ 13,215	$ 233,120	$ 1,495,833	$ (1,051)
Balance (in shares) at Dec. 31, 2020		63,424,526
Net income per consolidated statements of income	51,962			51,962
Other comprehensive income (loss), net of tax	(15,455)				(15,455)
Common stock dividends paid ($0.23 per share)	(14,685)			(14,685)
Shares withheld to pay taxes, long-term incentive plan	(1,230)	$ 24	(1,254)
Shares withheld to pay taxes, long-term incentive plan (in shares)		114,977
Repurchase and retirement of common stock	(4,185)	$ (30)	(4,155)
Repurchase and retirement of common stock (in shares)		(144,981)
Compensation expense, long-term incentive plan	2,181		2,181
Balance at Mar. 31, 2021	1,759,705	$ 13,209	229,892	1,533,110	(16,506)
Balance (in shares) at Mar. 31, 2021		63,394,522
Balance at Dec. 31, 2020	1,741,117	$ 13,215	233,120	1,495,833	(1,051)
Balance (in shares) at Dec. 31, 2020		63,424,526
Net income per consolidated statements of income	121,143
Other comprehensive income (loss), net of tax	(18,029)
Balance at Sep. 30, 2021	1,768,947	$ 13,014	201,837	1,573,176	(19,080)
Balance (in shares) at Sep. 30, 2021		62,461,832
Balance at Mar. 31, 2021	1,759,705	$ 13,209	229,892	1,533,110	(16,506)
Balance (in shares) at Mar. 31, 2021		63,394,522
Net income per consolidated statements of income	47,981			47,981
Other comprehensive income (loss), net of tax	5,865				5,865
Common stock dividends paid ($0.23 per share)	(14,640)			(14,640)
Shares withheld to pay taxes, long-term incentive plan	(11)	$ 2	(13)
Shares withheld to pay taxes, long-term incentive plan (in shares)		8,524
Repurchase and retirement of common stock	(20,805)	$ (132)	(20,673)
Repurchase and retirement of common stock (in shares)		(629,820)
Compensation expense, long-term incentive plan	1,214		1,214
Balance at Jun. 30, 2021	1,779,309	$ 13,079	210,420	1,566,451	(10,641)
Balance (in shares) at Jun. 30, 2021		62,773,226
Net income per consolidated statements of income	21,200			21,200
Other comprehensive income (loss), net of tax	(8,439)				(8,439)
Common stock dividends paid ($0.23 per share)	(14,475)			(14,475)
Shares withheld to pay taxes, long-term incentive plan	(96)	$ 1	(97)
Shares withheld to pay taxes, long-term incentive plan (in shares)		7,336
Repurchase and retirement of common stock	(9,668)	$ (66)	(9,602)
Repurchase and retirement of common stock (in shares)		(318,730)
Compensation expense, long-term incentive plan	1,116		1,116
Balance at Sep. 30, 2021	1,768,947	$ 13,014	201,837	1,573,176	(19,080)
Balance (in shares) at Sep. 30, 2021		62,461,832
Balance at Dec. 31, 2021	$ 1,741,311	$ 12,845	175,913	1,585,113	(32,560)
Balance (in shares) at Dec. 31, 2021	61,648,679	61,648,679
Net income per consolidated statements of income	$ 29,211			29,211
Other comprehensive income (loss), net of tax	(116,096)				(116,096)
Common stock dividends paid ($0.23 per share)	(14,186)			(14,186)
Shares withheld to pay taxes, long-term incentive plan	(1,009)	$ 19	(1,028)
Shares withheld to pay taxes, long-term incentive plan (in shares)		93,944
Repurchase and retirement of common stock	(9,094)	$ (58)	(9,036)
Repurchase and retirement of common stock (in shares)		(279,231)
Compensation expense, long-term incentive plan	1,245		1,245
Balance at Mar. 31, 2022	1,631,382	$ 12,806	167,094	1,600,138	(148,656)
Balance (in shares) at Mar. 31, 2022		61,463,392
Balance at Dec. 31, 2021	$ 1,741,311	$ 12,845	175,913	1,585,113	(32,560)
Balance (in shares) at Dec. 31, 2021	61,648,679	61,648,679
Net income per consolidated statements of income	$ 105,950
Other comprehensive income (loss), net of tax	(273,852)
Balance at Sep. 30, 2022	$ 1,508,945	$ 12,700	154,150	1,648,507	(306,412)
Balance (in shares) at Sep. 30, 2022	60,953,864	60,953,864
Balance at Mar. 31, 2022	$ 1,631,382	$ 12,806	167,094	1,600,138	(148,656)
Balance (in shares) at Mar. 31, 2022		61,463,392
Net income per consolidated statements of income	34,284			34,284
Other comprehensive income (loss), net of tax	(58,486)				(58,486)
Common stock dividends paid ($0.23 per share)	(14,212)			(14,212)
Shares withheld to pay taxes, long-term incentive plan	(7)		(7)
Shares withheld to pay taxes, long-term incentive plan (in shares)		513
Repurchase and retirement of common stock	(7,505)	$ (54)	(7,451)
Repurchase and retirement of common stock (in shares)		(262,782)
Compensation expense, long-term incentive plan	1,240		1,240
Balance at Jun. 30, 2022	1,586,696	$ 12,752	160,876	1,620,210	(207,142)
Balance (in shares) at Jun. 30, 2022		61,201,123
Net income per consolidated statements of income	42,455			42,455
Other comprehensive income (loss), net of tax	(99,270)				(99,270)
Common stock dividends paid ($0.23 per share)	(14,158)			(14,158)
Shares withheld to pay taxes, long-term incentive plan	(2)		(2)
Shares withheld to pay taxes, long-term incentive plan (in shares)		119
Repurchase and retirement of common stock	(8,005)	$ (52)	(7,953)
Repurchase and retirement of common stock (in shares)		(247,378)
Compensation expense, long-term incentive plan	1,229		1,229
Balance at Sep. 30, 2022	$ 1,508,945	$ 12,700	$ 154,150	$ 1,648,507	$ (306,412)
Balance (in shares) at Sep. 30, 2022	60,953,864	60,953,864