Loans and Allowance for Credit Losses - Loan Balances by Year of Origination and Performing and Nonperforming Status (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 210,517	$ 1,166,736
Year two	1,185,423	890,701
Year three	869,343	995,373
Year four	969,669	988,809
Year five	921,641	722,161
More than five years	2,455,514	1,900,975
Revolving	1,299,975	1,362,700
Revolving-Term	47,300	44,502
Total	7,959,382	8,071,957
Commercial loans | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	61,340	480,967
Year two	483,042	315,684
Year three	316,508	326,048
Year four	322,849	319,652
Year five	285,087	343,726
More than five years	1,328,472	1,093,130
Revolving	38,790	42,554
Revolving-Term	0	0
Total	2,836,088	2,921,761
Commercial loans | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	84,636	161,634
Year two	154,971	96,065
Year three	92,640	115,559
Year four	111,453	139,784
Year five	128,791	93,561
More than five years	266,555	184,888
Revolving	482,498	539,114
Revolving-Term	0	0
Total	1,321,544	1,330,605
Commercial loans | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	14,994	172,822
Year two	201,198	119,821
Year three	113,457	43,093
Year four	44,094	18,762
Year five	7,678	2,520
More than five years	3,699	1,260
Revolving	6,464	7,099
Revolving-Term	0	0
Total	391,584	365,377
Commercial loans | Business banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	30,136	182,401
Year two	178,415	132,590
Year three	126,890	206,281
Year four	195,888	199,780
Year five	194,857	161,293
More than five years	476,590	338,580
Revolving	95,612	93,856
Revolving-Term	1,026	1,082
Total	1,299,414	1,315,863
Consumer loans | Consumer real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	17,563	161,896
Year two	161,906	221,288
Year three	215,142	300,460
Year four	292,114	306,962
Year five	302,024	119,961
More than five years	378,508	281,990
Revolving	627,422	620,773
Revolving-Term	32,122	33,741
Total	2,026,801	2,047,071
Consumer loans | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,848	7,016
Year two	5,891	5,253
Year three	4,706	3,932
Year four	3,271	3,869
Year five	3,204	1,100
More than five years	1,690	1,127
Revolving	49,189	59,304
Revolving-Term	14,152	9,679
Total	$ 83,951	$ 91,280