Fair Value - Assets and Liabilities Measured at Fair Value on Non-Recurring Basis (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Commercial, industrial and agricultural
Impaired loans:
Assets, fair value disclosure	$ 5,417	$ 2,910
Commercial, industrial and agricultural | Quoted Prices in Active Markets  for Identical Assets
Impaired loans:
Assets, fair value disclosure	0	0
Commercial, industrial and agricultural | Significant Other Observable Inputs
Impaired loans:
Assets, fair value disclosure	0	0
Commercial, industrial and agricultural | Significant Unobservable Inputs
Impaired loans:
Assets, fair value disclosure	5,417	2,910
Commercial mortgages
Impaired loans:
Assets, fair value disclosure	10,981	1,147
Commercial mortgages | Quoted Prices in Active Markets  for Identical Assets
Impaired loans:
Assets, fair value disclosure	0	0
Commercial mortgages | Significant Other Observable Inputs
Impaired loans:
Assets, fair value disclosure	0	0
Commercial mortgages | Significant Unobservable Inputs
Impaired loans:
Assets, fair value disclosure	$ 10,981	$ 1,147