Funds Borrowed - Schedule of Outstanding Balances of Funds Borrowed (Detail) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
2025		$ 753,655
2026		526,332
2027		354,570
2028		211,550
2029		214,739
Thereafter		83,250
Long term debt	[1]	$ 2,144,096	$ 2,117,189
Interest Rate	[2]	3.59%
Deposits [Member]
Debt Instrument [Line Items]
2025	[3]	$ 721,155
2026	[3]	479,582
2027	[3]	350,070
2028	[3]	157,800
2029	[3]	173,239
Thereafter	[3]	0
Long term debt	[1],[3]	$ 1,881,846	1,869,439
Interest Rate	[2],[3]	3.17%
Retail And Privately Placed Notes [Member]
Debt Instrument [Line Items]
2025		$ 0
2026		31,250
2027		0
2028		53,750
2029		39,000
Thereafter		12,500
Long term debt	[1]	$ 136,500	139,500
Interest Rate	[2]	8.08%
SBA debentures and borrowings
Debt Instrument [Line Items]
2025		$ 12,500
2026		15,500
2027		4,500
2028		0
2029		2,500
Thereafter		37,750
Long term debt	[1]	$ 72,750	75,250
Interest Rate	[2]	3.54%
Trust Preferred Securities [Member]
Debt Instrument [Line Items]
2025		$ 0
2026		0
2027		0
2028		0
2029		0
Thereafter		33,000
Long term debt	[1]	$ 33,000	33,000
Interest Rate	[2]	7.71%
Federal Reserve and Other Borrowings [Member]
Debt Instrument [Line Items]
2025		$ 20,000
2026		0
2027		0
2028		0
2029		0
Thereafter		0
Long term debt	[1]	$ 20,000	$ 0
Interest Rate	[2]	5.95%

[1] Excludes deferred financing costs of $8.5 million as of both March 31, 2024 and December 31, 2023.

[2] Weighted average contractual rate as of March 31, 2024.

[3] Balance excludes $1.5 million of strategic partner reserve deposits as of both March 31, 2024 and December 31, 2023.