Fair Value Measurements - Fair Value Measurement on Nonrecurring Basis (Details) - Nonrecurring - Impaired Loans - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair value measurements of assets on a nonrecurring basis
Basis	$ 374		$ 4,111
Fair Value	335		3,380
Net Losses (Gains) Recorded in Earnings	5	$ 0
Level 1
Fair value measurements of assets on a nonrecurring basis
Fair Value	0		0
Level 2
Fair value measurements of assets on a nonrecurring basis
Fair Value	0		0
Level 3
Fair value measurements of assets on a nonrecurring basis
Fair Value	335		3,380
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Fair value measurements of assets on a nonrecurring basis
Basis	374		4,111
Fair Value	335		3,380
Net Losses (Gains) Recorded in Earnings	5	$ 0
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Level 1
Fair value measurements of assets on a nonrecurring basis
Fair Value	0		0
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Level 2
Fair value measurements of assets on a nonrecurring basis
Fair Value	0		0
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Level 3
Fair value measurements of assets on a nonrecurring basis
Fair Value	$ 335		$ 3,380