Allowance for Credit Losses (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) item	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) item	Sep. 30, 2021 USD ($)
Allowance for credit losses
Number of classes existing in loan and lease portfolio | item	9		9
Changes in allowance for loan and lease losses
Balance at the beginning of the period	$ 132,865	$ 136,361	$ 127,492	$ 140,654
Charge-offs	720	1,077	1,171	6,323
Recoveries	424	1,030	1,512	2,610
Net charge-offs (recoveries)	296	47	(341)	3,713
Provision (recovery of provision)	3,167	(2,559)	7,903	(3,186)
Balance at the end of the period	135,736	133,755	135,736	133,755
Commercial and agricultural
Changes in allowance for loan and lease losses
Balance at the beginning of the period	16,110	14,832	15,409	16,680
Charge-offs	414	21	453	307
Recoveries	39	176	46	694
Net charge-offs (recoveries)	375	(155)	407	(387)
Provision (recovery of provision)	412	179	1,145	(1,901)
Balance at the end of the period	16,147	15,166	16,147	15,166
Solar
Changes in allowance for loan and lease losses
Balance at the beginning of the period	6,652	5,867	6,585	5,549
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Net charge-offs (recoveries)	0	0	0	0
Provision (recovery of provision)	142	(15)	209	303
Balance at the end of the period	6,794	5,852	6,794	5,852
Auto and light truck
Changes in allowance for loan and lease losses
Balance at the beginning of the period	19,057	27,221	19,624	28,926
Charge-offs	66	407	98	5,060
Recoveries	91	479	212	664
Net charge-offs (recoveries)	(25)	(72)	(114)	4,396
Provision (recovery of provision)	(85)	(1,451)	(741)	1,312
Balance at the end of the period	18,997	25,842	18,997	25,842
Medium and heavy duty truck
Changes in allowance for loan and lease losses
Balance at the beginning of the period	6,709	5,888	6,015	6,400
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Net charge-offs (recoveries)	0	0	0	0
Provision (recovery of provision)	304	(158)	998	(670)
Balance at the end of the period	7,013	5,730	7,013	5,730
Aircraft
Changes in allowance for loan and lease losses
Balance at the beginning of the period	36,987	35,301	33,628	34,053
Charge-offs	0	0	0	0
Recoveries	176	153	653	513
Net charge-offs (recoveries)	(176)	(153)	(653)	(513)
Provision (recovery of provision)	132	975	3,014	1,863
Balance at the end of the period	37,295	36,429	37,295	36,429
Construction equipment
Changes in allowance for loan and lease losses
Balance at the beginning of the period	21,171	17,908	19,673	19,166
Charge-offs	0	551	48	559
Recoveries	11	170	11	424
Net charge-offs (recoveries)	(11)	381	37	135
Provision (recovery of provision)	1,667	(1,083)	3,213	(2,587)
Balance at the end of the period	22,849	16,444	22,849	16,444
Commercial real estate
Changes in allowance for loan and lease losses
Balance at the beginning of the period	18,416	22,578	19,691	22,758
Charge-offs	0	0	0	0
Recoveries	17	0	43	19
Net charge-offs (recoveries)	(17)	0	(43)	(19)
Provision (recovery of provision)	57	(1,253)	(1,244)	(1,452)
Balance at the end of the period	18,490	21,325	18,490	21,325
Residential real estate and home equity
Changes in allowance for loan and lease losses
Balance at the beginning of the period	5,779	5,066	5,084	5,374
Charge-offs	17	0	27	42
Recoveries	1	3	129	14
Net charge-offs (recoveries)	16	(3)	(102)	28
Provision (recovery of provision)	306	96	883	(181)
Balance at the end of the period	6,069	5,165	6,069	5,165
Consumer
Changes in allowance for loan and lease losses
Balance at the beginning of the period	1,984	1,700	1,783	1,748
Charge-offs	223	98	545	355
Recoveries	89	49	418	282
Net charge-offs (recoveries)	134	49	127	73
Provision (recovery of provision)	232	151	426	127
Balance at the end of the period	$ 2,082	$ 1,802	$ 2,082	$ 1,802