Condensed Financial Information - Parent Company - Condensed Statements of Earnings (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income:
Total interest income		$ 528,070	$ 432,854	$ 376,405
Expenses:
Salaries, commissions and employee benefits		131,915	134,133	142,042
EARNINGS BEFORE INCOME TAXES		243,299	280,874	271,970
INCOME TAX EXPENSE		44,322	46,399	44,408
NET EARNINGS		198,977	234,475	227,562
Parent Company [Member]
Income:
Cash dividends from subsidiaries	[1]	133,500	67,500	96,500
Excess of earnings over dividends of subsidiaries	[1]	72,444	174,741	140,441
Other		1,783	62	279
Total interest income		207,727	242,303	237,220
Expenses:
Salaries, commissions and employee benefits		6,129	6,541	7,374
Other operating expenses		4,521	4,106	5,262
Total expense		10,650	10,647	12,636
EARNINGS BEFORE INCOME TAXES		197,077	231,656	224,584
INCOME TAX EXPENSE		1,900	2,819	2,978
NET EARNINGS		$ 198,977	$ 234,475	$ 227,562

[1] Eliminates in consolidation