Fair Value Measurements - Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands		Mar. 31, 2026		Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		$ 2,656,332	[1]	$ 2,454,058	[2]
Equity Securities, FV-NI		1,082		2
Other Borrowings, Fair Value Disclosure		111,250		113,634
Credit-linked notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Borrowings, Fair Value Disclosure		111,250		113,634
Agency commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		50,981		50,966
Agency residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		1,104,183		871,624
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		231,958		241,596
Private label residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		233,184		228,975
Collateralized loan obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		200,374		200,822
Private label commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		8,270		9,279
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		12,661		13,249
SBA securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		3,060		3,462
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrants Not Settleable in Cash, Fair Value Disclosure				3,437
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		2,656,332		2,454,058
Cash Flow Hedge Derivative Instrument Assets at Fair Value	[3]	5,818
Interest rate and foreign exchange contracts		4,362	[3]	4,124
Warrants Not Settleable in Cash, Fair Value Disclosure		3,363	[3]	3,437
Cash flow hedges in Cash, Fair Value Disclosure, Liabilities		1,838		4,065
Derivative Liability, Fair Value of Collateral		4,461		4,156
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise pass through securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		811,661		834,085
Fair Value, Measurements, Recurring | Agency commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		50,981		50,966
Fair Value, Measurements, Recurring | Agency residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		1,104,183		871,624
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		231,958		241,596
Fair Value, Measurements, Recurring | Private label residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		233,184		228,975
Fair Value, Measurements, Recurring | Collateralized loan obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		200,374		200,822
Fair Value, Measurements, Recurring | Private label commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		8,270		9,279
Fair Value, Measurements, Recurring | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		12,661		13,249
Fair Value, Measurements, Recurring | SBA securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		3,060		3,462
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Equity Securities, FV-NI		1,082		2
Cash Flow Hedge Derivative Instrument Assets at Fair Value		0
Interest rate and foreign exchange contracts		0		0
Warrants Not Settleable in Cash, Fair Value Disclosure		0		0
Cash flow hedges in Cash, Fair Value Disclosure, Liabilities		0		0
Derivative Liability, Fair Value of Collateral		0		0
Other Borrowings		0		0
Fair Value, Measurements, Recurring | Level 1 | Government agency and government-sponsored enterprise pass through securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 1 | Agency commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 1 | Agency residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 1 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 1 | Private label residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 1 | Collateralized loan obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 1 | Private label commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 1 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 1 | SBA securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		2,654,082		2,451,688
Equity Securities, FV-NI		0		0
Cash Flow Hedge Derivative Instrument Assets at Fair Value		5,818
Interest rate and foreign exchange contracts		4,362		4,124
Warrants Not Settleable in Cash, Fair Value Disclosure		0		0
Cash flow hedges in Cash, Fair Value Disclosure, Liabilities		1,838		4,065
Derivative Liability, Fair Value of Collateral		4,461		4,156
Other Borrowings		0		0
Fair Value, Measurements, Recurring | Level 2 | Government agency and government-sponsored enterprise pass through securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		811,661		834,085
Fair Value, Measurements, Recurring | Level 2 | Agency commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		50,981		50,966
Fair Value, Measurements, Recurring | Level 2 | Agency residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		1,104,183		871,624
Fair Value, Measurements, Recurring | Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		229,708		239,226
Fair Value, Measurements, Recurring | Level 2 | Private label residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		233,184		228,975
Fair Value, Measurements, Recurring | Level 2 | Collateralized loan obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		200,374		200,822
Fair Value, Measurements, Recurring | Level 2 | Private label commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		8,270		9,279
Fair Value, Measurements, Recurring | Level 2 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		12,661		13,249
Fair Value, Measurements, Recurring | Level 2 | SBA securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		3,060		3,462
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		2,250		2,370
Equity Securities, FV-NI		0		0
Cash Flow Hedge Derivative Instrument Assets at Fair Value		0
Interest rate and foreign exchange contracts		0		0
Warrants Not Settleable in Cash, Fair Value Disclosure		3,363		3,437
Cash flow hedges in Cash, Fair Value Disclosure, Liabilities		0		0
Derivative Liability, Fair Value of Collateral		0		0
Other Borrowings		111,250		113,634
Fair Value, Measurements, Recurring | Level 3 | Government agency and government-sponsored enterprise pass through securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 3 | Agency commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 3 | Agency residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		2,250		2,370
Fair Value, Measurements, Recurring | Level 3 | Private label residential CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 3 | Collateralized loan obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 3 | Private label commercial MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 3 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		0		0
Fair Value, Measurements, Recurring | Level 3 | SBA securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value, net of allowance for credit losses (amortized cost of $2,857,903 and $2,646,414, respectively)		$ 0		$ 0

[1] Excludes accrued interest receivable of $12.3 million at March 31, 2026 which is recorded in "Other assets" on the consolidated balance sheets.

[2] Excludes accrued interest receivable of $11.4 million at December 31, 2025 which is recorded in "Other assets" on the consolidated balance sheets.

[3] For information regarding derivative instruments, see "Note 9. Derivatives".