Derivative Instruments and Hedging Activities - Additional Information (Details)				3 Months Ended		6 Months Ended
	Jul. 28, 2020 USD ($) Derivative	Jun. 24, 2016	Jul. 01, 2010	Jun. 30, 2020 USD ($) Derivative	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) Loan Derivative	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Derivative Instruments and Hedging Activities [Abstract]
Frequency of repricing						3 months
Interest expense				$ 49,000	$ 50,000	$ 99,000	$ 99,000
Interest Rate Swaps - Junior Subordinated Debt Due 2036 [Member]
Derivative Instruments and Hedging Activities [Abstract]
Period to convert floating rate liability to fixed rate liability under agreement		2031
Fixed interest rate				3.21%	3.21%	3.21%	3.21%
Interest Rate Swaps - Junior Subordinated Debt Due 2036 [Member] | LIBOR [Member]
Derivative Instruments and Hedging Activities [Abstract]
Term of variable rate						3 months
Basis spread on variable rate				1.70%		1.70%
Interest Rate Swaps - Junior Subordinated Debt Due 2036 [Member] | Maximum [Member]
Derivative Instruments and Hedging Activities [Abstract]
Period to convert floating rate liability to fixed rate liability under agreement			2020
Interest Rate Swap through 6-15-2031 [Member]
Derivative Instruments and Hedging Activities [Abstract]
Interest expense				$ 0	$ 0	$ 0	$ 0
Interest Rate Swap through 9-15-2020 [Member]
Derivative Instruments and Hedging Activities [Abstract]
Interest expense				27,900	6,300	$ 41,200	10,900
Interest Rate Swap [Member]
Derivative Instruments and Hedging Activities [Abstract]
Expiration date						Sep. 15, 2020
Cash collateral				$ 1,100,000		$ 1,100,000		$ 730,000
Interest Rate Swaps - Commercial Loans [Member]
Derivative Instruments and Hedging Activities [Abstract]
Number of swap agreements | Derivative				2		2
Number of commercial loans managed with swap agreements | Loan						2
Interest income					$ 9,100		$ 18,100
Interest expense				$ 16,200		$ 18,000
Interest Rate Swaps - Commercial Loans [Member] | Subsequent Event [Member]
Derivative Instruments and Hedging Activities [Abstract]
Notional/contract amount	$ 1,200,000
Termination fee	$ 89,200
Number of swap agreements terminated | Derivative	1
Interest Rate Swaps - Commercial Loans [Member] | LIBOR [Member]
Derivative Instruments and Hedging Activities [Abstract]
Term of variable rate						1 month
Interest Rate Swaps - Commercial Loans [Member] | Maximum [Member]
Derivative Instruments and Hedging Activities [Abstract]
Period to convert fixed rate assets to floating rate assets under agreement						2025
Interest Rate Swaps - Commercial Loans [Member] | Minimum [Member]
Derivative Instruments and Hedging Activities [Abstract]
Period to convert fixed rate assets to floating rate assets under agreement						2022