Junior Subordinated Debentures - Additional Information (Details) - USD ($)		3 Months Ended		12 Months Ended
	Feb. 25, 2020	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Debt Instrument [Line Items]
Principal amount		$ 46,500,000		$ 46,500,000
Other non-interest expense		4,615,000	$ 4,082,000
Metropolitan Statutory Trust 1
Debt Instrument [Line Items]
Principal amount		$ 35,000,000		$ 35,000,000
Metropolitan Statutory Trust 1 | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate		3.63%		4.69%
Accrued interest payable		$ 55,000		$ 71,000
Metropolitan Statutory Trust 1 | Junior Subordinated Debentures | Three-month LIBOR
Debt Instrument [Line Items]
Interest rate spread		2.79%		2.79%
RidgeStone Capital Trust I
Debt Instrument [Line Items]
Principal amount		$ 1,500,000		$ 1,500,000
RidgeStone Capital Trust I | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate		6.38%		6.38%
Accrued interest payable		$ 0		$ 0
Other non-interest expense	$ 112,000
RidgeStone Capital Trust I | Junior Subordinated Debentures | Five-year LIBOR
Debt Instrument [Line Items]
Interest rate spread		3.50%		3.50%
First Evanston Bancorp Trust I
Debt Instrument [Line Items]
Principal amount		$ 10,000,000		$ 10,000,000
First Evanston Bancorp Trust I | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate		2.52%		3.67%
Accrued interest payable		$ 12,000		$ 17,000
First Evanston Bancorp Trust I | Junior Subordinated Debentures | Three-month LIBOR
Debt Instrument [Line Items]
Interest rate spread		1.78%		1.78%