Loans and Allowance for Credit Losses on Loans - Defaults on Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2020 USD ($) contract	Sep. 30, 2020 USD ($) loan	Sep. 30, 2020 USD ($) item	Sep. 30, 2019 item	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($) contract	Sep. 30, 2020 USD ($) loan	Sep. 30, 2019 contract	Dec. 31, 2019 USD ($)
Allowance for Credit Losses on Loans
Number of troubled debt restructurings in which the amount of principal or accrued interest owed from the borrower was forgiven | loan		0					0
Number of loans modified as troubled debt restructurings during the period	7	7				10	10	2
Recorded investment of troubled debt restructurings | $	$ 1,182	$ 1,182	$ 1,182		$ 1,182	$ 1,182	$ 1,182		$ 1,039
Default period contractually past due under modified terms (in days)					30 days
Number of defaults on troubled debt restructurings | item			0	0
Period of consecutive payments (in months)					6 months