Loans and Allowance for Credit Losses - Allowance for Credit Loss Activity (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 107,966	$ 101,340	$ 101,340
Provision for credit losses on loans	3,425	1,090
Charge-offs	(6,939)	(4,459)	(24,638)
Recoveries	350	9,574
Net Recoveries/(Charge-offs)	(6,589)	5,115
Balance at End of Period	104,802	108,113	107,966
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		568	568
Commercial Loans | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	37,886	41,428	41,428
Provision for credit losses on loans	2,838	(1,011)
Charge-offs	(5,205)	0	(1,706)
Recoveries	93	9
Net Recoveries/(Charge-offs)	(5,112)	9
Balance at End of Period	35,612	40,426	37,886
Commercial Loans | Commercial real estate | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		0	0
Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	34,538	25,710	25,710
Provision for credit losses on loans	680	(476)
Charge-offs	(1,128)	(3,412)	(19,254)
Recoveries	117	9,400
Net Recoveries/(Charge-offs)	(1,011)	5,988
Balance at End of Period	34,207	31,297	34,538
Commercial Loans | Commercial and industrial | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		75	75
Commercial Loans | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	5,382	6,264	6,264
Provision for credit losses on loans	(233)	412
Charge-offs	0	0	(451)
Recoveries	0	2
Net Recoveries/(Charge-offs)	0	2
Balance at End of Period	5,149	6,893	5,382
Commercial Loans | Commercial construction | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		215	215
Commercial Loans | Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	12,858	12,547	12,547
Provision for credit losses on loans	(995)	1,497
Charge-offs	(98)	(652)	(1,306)
Recoveries	33	37
Net Recoveries/(Charge-offs)	(65)	(615)
Balance at End of Period	11,798	13,680	12,858
Commercial Loans | Business banking | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		251	251
Consumer Loans | Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	14,663	12,105	12,105
Provision for credit losses on loans	859	488
Charge-offs	(139)	(77)	(421)
Recoveries	27	61
Net Recoveries/(Charge-offs)	(112)	(16)
Balance at End of Period	15,410	12,855	14,663
Consumer Loans | Consumer real estate | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		278	278
Consumer Loans | Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	2,639	3,286	3,286
Provision for credit losses on loans	276	180
Charge-offs	(369)	(318)	(1,500)
Recoveries	80	65
Net Recoveries/(Charge-offs)	(289)	(253)
Balance at End of Period	$ 2,626	2,962	2,639
Consumer Loans | Other consumer | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		$ (251)	$ (251)