Condensed Financial Information - Parent Company - Condensed Balance Sheets (Details) - USD ($)		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Mar. 27, 2020	Dec. 31, 2019
ASSETS
Interest-bearing deposits in subsidiary bank		$ 37,392,000	$ 323,535,000
Total cash and cash equivalents		330,678,000	528,588,000	$ 729,084,000		$ 282,604,000
Securities available-for-sale, at fair value		5,474,359,000	6,573,179,000
Other assets		322,523,000	170,834,000
Total assets		12,974,066,000	13,102,461,000
LIABILITIES AND SHAREHOLDERS’ EQUITY
Total liabilities		11,708,329,000	11,343,237,000
SHAREHOLDERS’ EQUITY:
Common stock		1,427,000	1,425,000
Capital surplus		677,593,000	676,871,000
Retained earnings		1,121,945,000	981,675,000		$ 466,000
Accumulated other comprehensive earnings		(535,228,000)	99,253,000
Total shareholders’ equity		1,265,737,000	1,759,224,000	1,678,190,000		1,227,197,000
Total liabilities and shareholders’ equity		12,974,066,000	13,102,461,000
Subsidiary Bank [Member]
ASSETS
Cash in banks	[1]	50,204,000	83,547,000
Interest-bearing deposits in subsidiary bank	[1]	69,053,000	68,814,000
Unaffiliated Banks [Member]
ASSETS
Cash in banks	[1]	2,000	2,000
Parent Company [Member]
ASSETS
Total cash and cash equivalents		119,259,000	152,363,000	$ 136,666,000		$ 125,076,000
Securities available-for-sale, at fair value		2,235,000	2,489,000
Investment in and advances to subsidiaries, at equity	[1]	1,171,095,000	1,629,387,000
Intangible assets		723,000	723,000
Other assets		5,355,000	3,610,000
Total assets		1,298,667,000	1,788,572,000
LIABILITIES AND SHAREHOLDERS’ EQUITY
Total liabilities		32,930,000	29,348,000
SHAREHOLDERS’ EQUITY:
Common stock		1,427,000	1,425,000
Capital surplus		677,593,000	676,871,000
Retained earnings		1,121,945,000	981,675,000
Treasury stock		(11,035,000)	(10,090,000)
Deferred compensation		11,035,000	10,090,000
Accumulated other comprehensive earnings		(535,228,000)	99,253,000
Total shareholders’ equity		1,265,737,000	1,759,224,000
Total liabilities and shareholders’ equity		$ 1,298,667,000	$ 1,788,572,000

[1] Eliminates in consolidation.