Condensed Financial Information - Parent Company - Condensed Statements of Earnings (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income:
Total interest income		$ 432,854	$ 376,405	$ 364,128
Expenses:
Salaries, commissions and employee benefits		134,133	142,042	135,123
EARNINGS BEFORE INCOME TAXES		280,874	271,970	242,365
Income tax benefit		(46,399)	(44,408)	(40,331)
NET EARNINGS		234,475	227,562	202,034
Parent Company [Member]
Income:
Cash dividends from subsidiaries	[1]	67,500	96,500	87,500
Excess of earnings over dividends of subsidiaries	[1]	174,741	140,441	122,997
Other		62	279	8,368
Total interest income		242,303	237,220	218,865
Expenses:
Salaries, commissions and employee benefits		6,541	7,374	13,795
Other operating expenses		4,106	5,262	5,599
Total expense		10,647	12,636	19,394
EARNINGS BEFORE INCOME TAXES		231,656	224,584	199,471
Income tax benefit		(2,819)	2,978	2,563
NET EARNINGS		$ 234,475	$ 227,562	$ 202,034

[1] Eliminates in consolidation