Subordinated Debentures - Schedule of outstanding subordinated debentures (Details) - USD ($)	3 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Current Principal Balance	$ 505,403,000
Carrying Value	$ 501,611,000	$ 501,511,000
Subordinated notes
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	7.125%
Current Principal Balance	$ 495,000,000
Carrying Value	$ 493,474,000	493,410,000
Subordinated notes \| Subordinated notes due 2024, 5.75% per annum
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	5.75%
Current Principal Balance	$ 60,000,000
Carrying Value	$ 59,581,000	59,552,000
Subordinated notes \| Subordinated notes due 2029, 4.875% per annum until May 15, 2024, 3-month LIBOR +2.5% thereafter
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	4.875%
Current Principal Balance	$ 125,000,000
Carrying Value	$ 122,941,000	122,877,000
Subordinated notes \| Subordinated notes due 2029, 4.875% per annum until May 15, 2024, 3-month LIBOR +2.5% thereafter \| LIBOR
Debt Instrument [Line Items]
Variable rate	2.50%
Subordinated notes \| Subordinated notes due 2030, 5.375% per annum until June 15, 2025, 3-month SOFR +5.170% thereafter
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	5.375%
Current Principal Balance	$ 150,000,000
Carrying Value	$ 147,567,000	147,501,000
Subordinated notes \| Subordinated notes due 2030, 5.375% per annum until June 15, 2025, 3-month SOFR +5.170% thereafter \| SOFR
Debt Instrument [Line Items]
Variable rate	5.17%
Subordinated notes \| Subordinated notes due 2025, 7.125% per annum
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	7.125%
Current Principal Balance	$ 25,000,000
Carrying Value	$ 25,103,000	25,109,000
Subordinated notes \| Subordinated notes due 2026, 5.50% per annum until June 30 2021, 3-month LIBOR +4.285% thereafter
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	5.50%
Current Principal Balance	$ 135,000,000
Carrying Value	$ 138,282,000	138,371,000
Subordinated notes \| Subordinated notes due 2026, 5.50% per annum until June 30 2021, 3-month LIBOR +4.285% thereafter \| LIBOR
Debt Instrument [Line Items]
Variable rate	4.285%
Subordinated debt
Debt Instrument [Line Items]
Current Principal Balance	$ 10,403,000
Carrying Value	8,137,000	8,101,000
Subordinated debt \| Heritage Oaks Bancorp
Debt Instrument [Line Items]
Current Principal Balance	$ 5,248,000
Current Interest Rate	1.96%
Carrying Value	$ 4,138,000	4,121,000
Subordinated debt \| Heritage Oaks Bancorp \| LIBOR
Debt Instrument [Line Items]
Variable rate	1.72%
Subordinated debt \| Santa Lucia Bancorp (CA) Capital Trust
Debt Instrument [Line Items]
Current Principal Balance	$ 5,155,000
Current Interest Rate	1.72%
Carrying Value	$ 3,999,000	$ 3,980,000
Subordinated debt \| Santa Lucia Bancorp (CA) Capital Trust \| LIBOR
Debt Instrument [Line Items]
Variable rate	1.48%

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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