Securities - Unrealized Loss on Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
AVAILABLE FOR SALE
Less than 12 Months, fair value	$ 298,580	$ 1,174,855
Less than 12 Months, unrealized loss	10,006	82,638
More than 12 Months, fair value	671,293	29,165
More than 12 Months, unrealized Loss	60,818	7,504
Total fair value	969,873	1,204,020
Total unrealized loss	70,824	90,142
HELD TO MATURITY
Less than 12 months, fair value	187,387	672,739
Less than 12 months, unrealized loss	13,241	83,876
More than 12 months, fair value	799,070	340,055
More than 12 months, unrealized loss	153,939	98,262
Total fair value	986,457	1,012,794
Total unrealized loss	167,180	182,138
State and political subdivisions
AVAILABLE FOR SALE
Less than 12 Months, fair value	116,217	859,270
Less than 12 Months, unrealized loss	1,862	68,683
More than 12 Months, fair value	602,120	26,620
More than 12 Months, unrealized Loss	54,798	6,874
Total fair value	718,337	885,890
Total unrealized loss	56,660	75,557
HELD TO MATURITY
Less than 12 months, fair value	140,247	426,382
Less than 12 months, unrealized loss	7,452	66,898
More than 12 months, fair value	606,783	323,385
More than 12 months, unrealized loss	132,164	96,385
Total fair value	747,030	749,767
Total unrealized loss	139,616	163,283
Corporate bonds and other
AVAILABLE FOR SALE
Less than 12 Months, fair value	12,786	3,678
Less than 12 Months, unrealized loss	1,559	14
More than 12 Months, fair value	0	0
More than 12 Months, unrealized Loss	0	0
Total fair value	12,786	3,678
Total unrealized loss	1,559	14
HELD TO MATURITY
Less than 12 months, fair value	29,119	125,250
Less than 12 months, unrealized loss	4,522	6,660
More than 12 months, fair value	98,082	12,738
More than 12 months, unrealized loss	12,373	1,333
Total fair value	127,201	137,988
Total unrealized loss	16,895	7,993
Residential
AVAILABLE FOR SALE
Less than 12 Months, fair value	169,577	306,294
Less than 12 Months, unrealized loss	6,585	13,623
More than 12 Months, fair value	61,126	0
More than 12 Months, unrealized Loss	5,036	0
Total fair value	230,703	306,294
Total unrealized loss	11,621	13,623
HELD TO MATURITY
Less than 12 months, fair value	18,021	80,801
Less than 12 months, unrealized loss	1,267	7,799
More than 12 months, fair value	66,019	3,932
More than 12 months, unrealized loss	6,958	544
Total fair value	84,040	84,733
Total unrealized loss	8,225	8,343
Commercial
AVAILABLE FOR SALE
Less than 12 Months, fair value	0	5,613
Less than 12 Months, unrealized loss	0	318
More than 12 Months, fair value	8,047	2,545
More than 12 Months, unrealized Loss	984	630
Total fair value	8,047	8,158
Total unrealized loss	984	948
HELD TO MATURITY
Less than 12 months, fair value	0	40,306
Less than 12 months, unrealized loss	0	2,519
More than 12 months, fair value	28,186	0
More than 12 months, unrealized loss	2,444	0
Total fair value	28,186	40,306
Total unrealized loss	$ 2,444	$ 2,519