Subordinated Debentures (Details)		1 Months Ended			6 Months Ended
	Nov. 01, 2017 USD ($) note	May 31, 2019 USD ($)	Aug. 31, 2014 USD ($)	Mar. 31, 2004 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jul. 01, 2018 USD ($)	Jun. 30, 2018 USD ($)	Apr. 01, 2017 USD ($)
Subordinated Debentures
Subordinated debentures					$ 232,944,000	$ 110,313,000
PPBI Trust I
Subordinated Debentures
Floating Rate Trust Preferred Securities issue amount				$ 10,000,000.0
Notes
Subordinated Debentures
Debt issued			$ 60,000,000
Fixed interest rate (as a percent)			5.75%
Contribution of net proceeds from the Private Placement to the Bank to support general corporate purposes			$ 50,000,000
Subordinated debentures					59,400,000
Unamortized debt issuance cost					$ 628,000
Subordinated Debentures
Subordinated Debentures
Effective rate (as a percent)					5.35%
Subordinated Debentures | Notes II
Subordinated Debentures
Debt issued		$ 125,000,000
Fixed interest rate (as a percent)		4.875%
Unamortized debt issuance cost								$ 2,500,000
Floating rate junior subordinated debt								$ 122,500,000
Public offering price (as a percent)		100.00%
Subordinated Debentures | Mission Community Capital Trust I
Subordinated Debentures
Subordinated debentures					$ 2,800,000
Effective rate (as a percent)					5.55%
Floating rate junior subordinated debt									$ 3,100,000
Purchase accounting fair value adjustments					$ 296,000
Subordinated Debentures | Santa Lucia Bancorp (CA) Capital Trust
Subordinated Debentures
Subordinated debentures					$ 3,900,000
Effective rate (as a percent)					4.08%
Floating rate junior subordinated debt									5,200,000
Purchase accounting fair value adjustments					$ 1,300,000
Subordinated Debentures | Heritage Oaks Bancorp
Subordinated Debentures
Effective rate (as a percent)					4.31%
Floating rate junior subordinated debt					$ 4,000,000.0				$ 5,200,000
Purchase accounting fair value adjustments					1,200,000
Subordinated Debentures | Plaza Bancorp
Subordinated Debentures
Floating rate junior subordinated debt					25,100,000
Purchase accounting fair value adjustments					$ 145,000
Subordinated Debentures | Grandpoint Capital, Inc.
Subordinated Debentures
Effective rate (as a percent)					5.54%
Floating rate junior subordinated debt					$ 4,900,000
Purchase accounting fair value adjustments					$ (217,000)
Debt assumed in acquisition							$ 5,200,000
Subordinated Debentures | LIBOR
Subordinated Debentures
Floating interest rate, basis points added to base rate (as a percent)					2.75%
Subordinated Debentures | LIBOR | Notes II
Subordinated Debentures
Floating interest rate, basis points added to base rate (as a percent)		2.50%
Subordinated Debentures | LIBOR | Mission Community Capital Trust I
Subordinated Debentures
Floating interest rate, basis points added to base rate (as a percent)					2.95%
Subordinated Debentures | LIBOR | Santa Lucia Bancorp (CA) Capital Trust
Subordinated Debentures
Floating interest rate, basis points added to base rate (as a percent)					1.48%
Subordinated Debentures | LIBOR | Heritage Oaks Bancorp
Subordinated Debentures
Floating interest rate, basis points added to base rate (as a percent)					1.72%
Subordinated Debentures | LIBOR | Grandpoint Capital, Inc.
Subordinated Debentures
Floating interest rate, basis points added to base rate (as a percent)					2.95%
Subordinated Debentures | PPBI Trust I
Subordinated Debentures
Debt issued				$ 10,300,000
Minority interest purchased (as a percent)				3.00%
Amount of minority interest purchased				$ 310,000
Subordinated Notes 7.125% | Plaza Bancorp
Subordinated Debentures
Fixed interest rate (as a percent)	7.125%
Number of subordinated notes assumed | note	3
Debt assumed in acquisition	$ 25,000,000.0
Redemption price (as a percent)	103.00%
Redemption price, subsequent reduction (as a percent)	0.50%