Allowance for Credit Losses - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, collectively evaluated for impairment	$ 7,859,285		$ 7,766,319
Financing receivable, allowance for credit losses, collectively evaluated for impairment	67,995		66,173
Financing receivable, individually evaluated for impairment and acquired with deteriorated credit quality	93,300
Financing receivable, allowance for credit losses, individually evaluated for impairment and acquired with deteriorated credit quality	3,400
Loans, individually evaluated for impairment	11,827		16,268
Allowance for credit losses, Individually evaluated for impairment	3,408		4,091
Charge-offs	139	$ 7,804
Allowance for credit loss, available for sale	160	1,267	310	$ 83
Allowance for credit loss, held to maturity	157	199	107	$ 181
Debt securities, accrued interest after allowance for credit loss	9,100		8,700
Off-balance sheet, credit loss, liability	3,100		$ 3,000
Off-balance sheet, credit loss, liability, credit loss expense (reversal)	140	440
Charge-offs	(6,640)	0
Provision for credit loss expense	6,490	1,184
Signature Bank
Financing Receivable, Allowance for Credit Loss [Line Items]
Charge-offs	(6,600)
Provision for credit loss expense	6,600
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, allowance for credit losses, individually evaluated for impairment and acquired with deteriorated credit quality	2,700
Loans, individually evaluated for impairment	81,400
Charge-offs	$ 139	$ 170