Fair Value of Assets and Liabilities - Quantitative Information about Level 3 Fair Value Measurements (Details) - Non-Recurring Measurements $ in Thousands		Sep. 30, 2020 USD ($) Input	Dec. 31, 2019 USD ($) Input
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned | $		$ 297	$ 1,983
Collateral-dependent loans, net of ACL | $		2,284	23
Level 3
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned | $		297	1,983
Collateral-dependent loans, net of ACL | $		2,284	23
Level 3 | Sales Comparison Approach
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned | $		297	1,983
Level 3 | Sales Comparison Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent loans, net of ACL | $		45
Level 3 | Sales Comparison Approach | Adjustments to comparables
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent loans, net of ACL | $			14
Level 3 | Cost Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent loans, net of ACL | $		943	$ 9
Level 3 | Combined Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent loans, net of ACL | $		$ 1,296
Level 3 | Minimum | Sales Comparison Approach
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned	[1]	0.080
Level 3 | Minimum | Sales Comparison Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned	[1]		0.060
Collateral-dependent impaired loans, net of ALLL	[1]	0.100
Level 3 | Minimum | Sales Comparison Approach | Adjustments to comparables
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned			0.000
Collateral-dependent impaired loans, net of ALLL			0.000
Level 3 | Minimum | Cost Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent impaired loans, net of ALLL	[1]	0.100	0.100
Level 3 | Minimum | Combined Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent impaired loans, net of ALLL	[1]	0.100
Level 3 | Maximum | Sales Comparison Approach
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned	[1]	0.100
Level 3 | Maximum | Sales Comparison Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned	[1]		0.100
Collateral-dependent impaired loans, net of ALLL	[1]	0.100
Level 3 | Maximum | Sales Comparison Approach | Adjustments to comparables
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned			0.111
Collateral-dependent impaired loans, net of ALLL			0.000
Level 3 | Maximum | Cost Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent impaired loans, net of ALLL	[1]	0.100	0.100
Level 3 | Maximum | Combined Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent impaired loans, net of ALLL	[1]	0.100
Level 3 | Weighted Average Range | Sales Comparison Approach
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned	[1]	0.090
Level 3 | Weighted Average Range | Sales Comparison Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned	[1]		0.073
Collateral-dependent impaired loans, net of ALLL	[1]	0.100
Level 3 | Weighted Average Range | Sales Comparison Approach | Adjustments to comparables
Quantitative Information About Level 3 Fair Value Measurements
Other real estate owned			0.045
Collateral-dependent impaired loans, net of ALLL			0.000
Level 3 | Weighted Average Range | Cost Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent impaired loans, net of ALLL	[1]	0.100	0.100
Level 3 | Weighted Average Range | Combined Approach | Selling costs
Quantitative Information About Level 3 Fair Value Measurements
Collateral-dependent impaired loans, net of ALLL	[1]	0.100

[1] The range for selling cost inputs represents reductions to the fair value of the assets.