Subordinated Debentures (Details)						1 Months Ended			12 Months Ended
	Oct. 07, 2019 USD ($)	Sep. 16, 2019	Jul. 08, 2019	Jul. 01, 2018 USD ($)	Nov. 01, 2017 USD ($) note	Sep. 30, 2019 USD ($)	May 31, 2019 USD ($)	Mar. 31, 2004 USD ($)	Dec. 31, 2019 USD ($) note	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Apr. 01, 2017 USD ($)	Aug. 31, 2014 USD ($)
Debt Instrument [Line Items]
Subordinated debentures									$ 215,145,000	$ 110,313,000
Increase to carrying value of subordinated debt									$ 104,800,000
Percentage increase to carrying value of subordinated debt									95.00%
Debt issued									$ 220,403,000
Redemption of aggregated amount									18,558,000	0	$ 0
Redemption of company capital instruments									$ 17,600,000
PPBI Trust I
Debt Instrument [Line Items]
Floating Rate Trust Preferred Securities issue amount								$ 10,000,000.0
Subordinated notes
Debt Instrument [Line Items]
Number of subordinated debt instruments | note									3
Subordinated debentures									$ 207,187,000	$ 84,470,000
Weighted average interest rate at year-end									5.37%	6.04%
Debt issued									$ 210,000,000
Subordinated notes | Mission Community Capital Trust I
Debt Instrument [Line Items]
Redemption of aggregated amount	$ 3,100,000
Long-term Debt												$ 3,100,000
Effective rate (as a percent)	5.25%
Loss on early debt extinguishment	$ (290,000)
Subordinated notes | Santa Lucia Bancorp (CA) Capital Trust
Debt Instrument [Line Items]
Subordinated debentures									$ 3,900,000			5,200,000
Effective rate (as a percent)									3.47%
Purchase accounting fair value adjustments									$ (1,300,000)
Subordinated notes | Heritage Oaks Bank
Debt Instrument [Line Items]
Long-term Debt												$ 5,200,000
Effective rate (as a percent)									3.82%
Purchase accounting fair value adjustments									$ (1,200,000)
Debt assumed in acquisition									4,100,000
Subordinated notes | Grandpoint Capital, Inc.
Debt Instrument [Line Items]
Redemption of aggregated amount				$ 5,200,000
Effective rate (as a percent)		5.36%
Debt assumed in acquisition				$ 5,200,000
Loss on early debt extinguishment						$ (214,000)
Subordinated notes | Plaza Bancorp
Debt Instrument [Line Items]
Purchase accounting fair value adjustments									133,000
Carrying value of subordinated notes									25,100,000
Subordinated notes | PPBI Trust I
Debt Instrument [Line Items]
Debt issued								$ 10,300,000
Redemption of aggregated amount									$ 10,400,000
Effective rate (as a percent)			5.35%
Minority interest purchased (as a percent)								3.00%
Amount of minority interest purchased								$ 310,000
Subordinated notes | LIBOR | Mission Community Capital Trust I
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)	2.95%
Subordinated notes | LIBOR | Santa Lucia Bancorp (CA) Capital Trust
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)									1.48%
Subordinated notes | LIBOR | Heritage Oaks Bank
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)									1.72%
Subordinated notes | LIBOR | Grandpoint Capital, Inc.
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)		2.95%
Subordinated notes | LIBOR | PPBI Trust I
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)			2.75%
Subordinated notes | Subordinated notes due 2029, 4.875% per annum until May 15, 2024, 3-month LIBOR 2.5% thereafter
Debt Instrument [Line Items]
Subordinated debentures									$ 122,622,000	$ 0
Debt issued							$ 125,000,000.0		125,000,000.0
Redemption of aggregated amount									$ 18,600,000
Fixed interest rate (as a percent)							4.875%		4.875%
Unamortized debt issuance costs									$ 2,400,000
Long-term Debt									$ 122,600,000
Public offering price							100.00%
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]
Floating interest rate, basis points added to base rate (as a percent)							2.50%		2.50%
Subordinated debt
Debt Instrument [Line Items]
Number of subordinated debt instruments | note									2
Subordinated debentures									$ 7,958,000	25,843,000
Debt issued									10,403,000
Subordinated debt | Mission Community Capital Trust I
Debt Instrument [Line Items]
Subordinated debentures									0	2,787,000
Subordinated debt | Santa Lucia Bancorp (CA) Capital Trust
Debt Instrument [Line Items]
Subordinated debentures									3,904,000	3,829,000
Debt issued									$ 5,155,000
Effective rate (as a percent)									3.47%
Subordinated debt | PPBI Trust I
Debt Instrument [Line Items]
Subordinated debentures									$ 0	$ 10,310,000
Subordinated debt | LIBOR | Mission Community Capital Trust I
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)									2.95%
Subordinated debt | LIBOR | Santa Lucia Bancorp (CA) Capital Trust
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)									1.48%
Subordinated debt | LIBOR | Heritage Oaks Bank
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)									1.72%
Subordinated debt | LIBOR | PPBI Trust I
Debt Instrument [Line Items]
Floating interest rate, basis points added to base rate (as a percent)									2.75%
Subordinated notes due 2024, 5.75% per annum
Debt Instrument [Line Items]
Subordinated debentures									$ 59,400,000
Debt issued													$ 60,000,000.0
Fixed interest rate (as a percent)													5.75%
Unamortized debt issuance costs									$ 568,000
Subordinated notes due 2025, 7.125% per annum | Plaza Bancorp
Debt Instrument [Line Items]
Fixed interest rate (as a percent)					7.125%
Debt assumed in acquisition					$ 25,000,000.0
Number of subordinated notes assumed | note					3
Redemption price (as a percent)					103.00%
Redemption price, subsequent reduction (as a percent)					0.50%