Subordinated Notes and Junior Subordinated Debentures - Junior Subordinated Debentures by Issuance (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	$ 45,000	$ 46,500
Total liability, at carrying value	36,331	37,334
Metropolitan Statutory Trust 1
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	35,000	35,000
RidgeStone Capital Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par		1,500
First Evanston Bancorp Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	10,000	10,000
Junior Subordinated Debentures
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Discount	$ (8,669)	$ (9,166)
Junior Subordinated Debentures | Metropolitan Statutory Trust 1
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Mar. 17, 2034
Contractual Rate	3.03%	4.69%
Junior Subordinated Debentures | Metropolitan Statutory Trust 1 | Three-month LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Three-month LIBOR + 2.79%
Interest Rate Spread	2.79%	2.79%
Junior Subordinated Debentures | RidgeStone Capital Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Jun. 30, 2033
Contractual Rate		6.38%
Junior Subordinated Debentures | RidgeStone Capital Trust I | Five-year LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Five-year LIBOR + 3.50%
Interest Rate Spread	3.50%	3.50%
Junior Subordinated Debentures | First Evanston Bancorp Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Mar. 15, 2035
Contractual Rate	2.03%	3.67%
Junior Subordinated Debentures | First Evanston Bancorp Trust I | Three-month LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Three-month LIBOR + 1.78%
Interest Rate Spread	1.78%	1.78%