Allowance for Credit Losses - Activity in ACL by Class of Loans and Leases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Rollforward of the Allowance for Credit Losses
Balance at beginning of year	$ 148,581	$ 148,942	$ 143,900	$ 157,262
Charge-offs	(4,449)	(5,065)	(15,929)	(14,945)
Recoveries	4,739	2,286	9,464	7,229
Provision	5,924	2,000	17,360	(1,383)
Balance at end of year	154,795	148,163	154,795	148,163
Commercial Lending
Rollforward of the Allowance for Credit Losses
Charge-offs			(2,572)
Commercial and Industrial
Rollforward of the Allowance for Credit Losses
Balance at beginning of year	13,810	15,924	14,564	20,080
Charge-offs	(784)	(328)	(2,572)	(1,277)
Recoveries	2,637	240	3,175	594
Provision	(1,963)	(703)	(1,467)	(4,264)
Balance at end of year	13,700	15,133	13,700	15,133
Commercial real estate
Rollforward of the Allowance for Credit Losses
Balance at beginning of year	39,887	44,726	43,810	42,951
Charge-offs		(750)		(750)
Recoveries				14
Provision	3,911	416	(12)	2,177
Balance at end of year	43,798	44,392	43,798	44,392
Construction
Rollforward of the Allowance for Credit Losses
Balance at beginning of year	9,871	5,367	5,843	9,773
Provision	333	(643)	4,361	(5,049)
Balance at end of year	10,204	4,724	10,204	4,724
Lease financing
Rollforward of the Allowance for Credit Losses
Balance at beginning of year	1,447	1,398	1,551	1,659
Recoveries				60
Provision	263	235	159	(86)
Balance at end of year	1,710	1,633	1,710	1,633
Residential mortgage
Rollforward of the Allowance for Credit Losses
Charge-offs			(394)
Residential mortgage | Residential Lending: Residential Mortgage
Rollforward of the Allowance for Credit Losses
Balance at beginning of year	32,803	33,635	35,175	34,364
Charge-offs		(1)	(122)	(1)
Recoveries	53	37	110	245
Provision	4,143	248	1,836	(689)
Balance at end of year	36,999	33,919	36,999	33,919
Residential mortgage | Home equity line
Rollforward of the Allowance for Credit Losses
Charge-offs			(272)
Home equity line | Home equity line
Rollforward of the Allowance for Credit Losses
Balance at beginning of year	11,806	4,734	8,296	5,642
Charge-offs			(272)	(1,163)
Recoveries	303	356	539	575
Provision	(682)	164	2,864	200
Balance at end of year	11,427	5,254	11,427	5,254
Consumer
Rollforward of the Allowance for Credit Losses
Balance at beginning of year	38,957	43,158	34,661	42,793
Charge-offs	(3,665)	(3,986)	(12,963)	(11,754)
Recoveries	1,746	1,653	5,640	5,741
Provision	(81)	2,283	9,619	6,328
Balance at end of year	$ 36,957	$ 43,108	$ 36,957	$ 43,108