Fair Value - Securities Available for Sale Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
State & political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 0
Purchases	422
Total gains or (losses):
Included in other comprehensive income (loss)	0
Transfers out of Level 3	(358)
Ending Balance	64	$ 0
Residential & multi-family mortgage
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	2,795	0
Purchases	0	2,796
Total gains or (losses):
Included in other comprehensive income (loss)	0	(1)
Transfers out of Level 3	(2,795)
Ending Balance	$ 0	$ 2,795