Summary of Significant Accounting Policies - Goodwill and Other Intangible Assets (Details)			1 Months Ended
	May 04, 2018	Apr. 06, 2018	May 31, 2018	Apr. 30, 2018	Aug. 31, 2015	Nov. 30, 2014
United American Bank
Goodwill and Other Intangible Assets
Useful life, amortization period	3 years
Tri Valley Bank
Goodwill and Other Intangible Assets
Useful life, amortization period		11 years
Core deposit | Focus
Goodwill and Other Intangible Assets
Useful life, amortization period					10 years
Core deposit | United American Bank
Goodwill and Other Intangible Assets
Useful life, amortization period			10 years
Core deposit | Tri Valley Bank
Goodwill and Other Intangible Assets
Useful life, amortization period				10 years
Below market-value lease | United American Bank
Goodwill and Other Intangible Assets
Useful life, amortization period			3 years
Below market-value lease | Tri Valley Bank
Goodwill and Other Intangible Assets
Useful life, amortization period				11 years
Customer relationship and brokered relationship | BVF/CSNK
Goodwill and Other Intangible Assets
Useful life, amortization period						10 years