Allowance for Credit Losses - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, collectively evaluated for impairment	$ 8,017,176			$ 8,017,176		$ 7,766,319
Financing receivable, allowance for credit losses, collectively evaluated for impairment	70,775			70,775		66,173
Financing receivable, individually evaluated for impairment and acquired with deteriorated credit quality	84,100			84,100
Financing receivable, allowance for credit losses, individually evaluated for impairment and acquired with deteriorated credit quality	3,200			3,200
Loans, individually evaluated for impairment	9,552			9,552		16,268
Allowance for credit losses, Individually evaluated for impairment	3,190			3,190		4,091
Charge-offs	148		$ 369	287	$ 8,173
Allowance for credit loss, available for sale	0	$ 160	2,802	0	2,802	310	$ 1,267	$ 83
Allowance for credit loss, held to maturity	146	157	190	146	190	107	$ 199	$ 181
Debt securities, accrued interest after allowance for credit loss	9,000			9,000		8,700
Off-balance sheet, credit loss, liability	2,800			2,800		$ 3,000
Off-balance sheet, credit loss, liability, credit loss expense (reversal)	(304)		535	(164)	975
Charge-offs	0		0	(6,640)
(Benefit) provision for credit loss expense	(160)		1,535	6,330	2,719
Signature Bank
Financing Receivable, Allowance for Credit Loss [Line Items]
Charge-offs		(6,600)
(Benefit) 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	2,500			2,500
Loans, individually evaluated for impairment	74,600			74,600
Charge-offs	$ 148		$ 369	$ 287	$ 539