Organization and Summary of Significant Accounting Policies - Cash and Cash Equivalents and Certificates of Deposit with other Banks (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash And Cash Equivalents [Line Items]
Daily average cash reserve requirement	$ 1,000	$ 1,700
Minimum | Certificates of Deposit
Cash And Cash Equivalents [Line Items]
Investment interest rate	0.20%
Maximum
Cash And Cash Equivalents [Line Items]
FDIC insurable amount	$ 250
Maximum | Certificates of Deposit
Cash And Cash Equivalents [Line Items]
Investment interest rate	3.55%