Borrowings (Details) $ in Thousands	6 Months Ended
Jun. 30, 2020 USD ($) Advance	Dec. 31, 2019 USD ($)
Debt Instruments [Abstract]
Short-term borrowings	$ 104,000
Long-term borrowings	599,102	$ 483,562
Total commitment on repurchase agreements	$ 35,000
Percentage of carrying value of qualifying one-to-four family loans	80.00%
Percentage of carrying value of qualifying home equity loans	75.00%
Percentage of carrying value of qualifying multi-family loans	64.00%
FHLBC stock as collateral	$ 26,700	21,200
Federal Home Loan Bank, Chicago [Member]
Debt Instruments [Abstract]
Short-term borrowings	$ 104,000	$ 0
Weighted average rate	0.20%	0.00%
Federal Home Loan Bank, Chicago Advances [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 599,102	$ 483,562
Weighted average rate	1.81%	2.11%
Repurchase Agreements [Member]
Debt Instruments [Abstract]
Short-term borrowings	$ 25,102	$ 13,562
Weighted average rate	3.25%	4.66%
Short Term Debt Maturing On July 7, 2020 [Member] \| First Advance [Member]
Debt Instruments [Abstract]
Short-term borrowings	$ 25,000
Maturity date	Jul. 07, 2020
Interest rate	0.19%
Number of short-term borrowings advances \| Advance	1
Short Term Debt Maturing On July 7, 2020 [Member] \| Second Advance [Member]
Debt Instruments [Abstract]
Short-term borrowings	$ 10,000
Maturity date	Jul. 07, 2020
Interest rate	0.28%
Number of short-term borrowings advances \| Advance	1
Short Term Debt Maturing on July 14, 2020 [Member]
Debt Instruments [Abstract]
Short-term borrowings	$ 20,000
Maturity date	Jul. 14, 2020
Interest rate	0.20%
Number of short-term borrowings advances \| Advance	1
Short Term Debt Maturing On July 20, 2020 [Member]
Debt Instruments [Abstract]
Short-term borrowings	$ 20,000
Maturity date	Jul. 20, 2020
Interest rate	0.19%
Number of short-term borrowings advances \| Advance	1
Short Term Debt Maturing On August 5, 2020 [Member]
Debt Instruments [Abstract]
Short-term borrowings	$ 25,000
Maturity date	Aug. 05, 2020
Interest rate	0.23%
Number of short-term borrowings advances \| Advance	1
Short Term Debt Maturing On May 1, 2020 [Member]
Debt Instruments [Abstract]
Short-term borrowings	$ 4,000
Maturity date	May 01, 2021
Interest rate	0.00%
Number of short-term borrowings advances \| Advance	1
Long Term Debt Maturing 2027 [Member] \| Federal Home Loan Bank, Chicago [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 50,000
FHLB, year of maturity	2027
FHLB, interest rate	1.73%
Long Term Debt Maturing 2027 [Member] \| Federal Home Loan Bank, Chicago Advances [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 50,000	$ 50,000
Weighted average rate	1.73%	1.73%
Long Term Debt Maturing 2028 [Member] \| Federal Home Loan Bank, Chicago [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 25,000
FHLB, year of maturity	2028
Number of FHLB advances \| Advance	1
Long Term Debt Maturing 2028 [Member] \| Federal Home Loan Bank, Chicago [Member] \| First Advance [Member]
Debt Instruments [Abstract]
FHLB, interest rate	2.16%
Long Term Debt Maturing 2028 [Member] \| Federal Home Loan Bank, Chicago [Member] \| Second Advance [Member]
Debt Instruments [Abstract]
FHLB, interest rate	2.40%
Long Term Debt Maturing 2028 [Member] \| FHLB Single Call Option in March 2021 [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 55,000
FHLB, year of maturity	2028
Number of FHLB advances \| Advance	2
FHLB, interest rate	2.27%
Long Term Debt Maturing 2028 [Member] \| FHLB Single Call Option in May 2021 [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 50,000
FHLB, year of maturity	2028
Number of FHLB advances \| Advance	2
Long Term Debt Maturing 2028 [Member] \| FHLB Single Call Option in May 2021 [Member] \| Minimum [Member]
Debt Instruments [Abstract]
FHLB, interest rate	2.34%
Long Term Debt Maturing 2028 [Member] \| FHLB Single Call Option in May 2021 [Member] \| Maximum [Member]
Debt Instruments [Abstract]
FHLB, interest rate	2.48%
Long Term Debt Maturing 2028 [Member] \| FHLB Quarterly Call Option in June 2020 [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 50,000
FHLB, year of maturity	2028
Number of FHLB advances \| Advance	1
FHLB, interest rate	2.34%
Long Term Debt Maturing 2028 [Member] \| FHLB Quarterly Call Option in September 2020 [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 50,000
FHLB, year of maturity	2028
Number of FHLB advances \| Advance	1
FHLB, interest rate	2.57%
Long Term Debt Maturing 2028 [Member] \| Federal Home Loan Bank, Chicago Advances [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 255,000	$ 255,000
Weighted average rate	2.37%	2.37%
Long Term Debt Maturing 2029 [Member] \| FHLB Quarterly Call Option in May 2022 [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 50,000
FHLB, year of maturity	2029
Number of FHLB advances \| Advance	1
FHLB, interest rate	1.98%
Long Term Debt Maturing 2029 [Member] \| FHLB Quarterly Call Option in August 2021 [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 50,000
FHLB, year of maturity	2029
Number of FHLB advances \| Advance	1
FHLB, interest rate	1.75%
Long Term Debt Maturing 2029 [Member] \| FHLB Quarterly Call Option in November 2020 [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 25,000
FHLB, year of maturity	2029
Number of FHLB advances \| Advance	1
FHLB, interest rate	1.52%
Long Term Debt Maturing 2029 [Member] \| FHLB Quarterly Call Option [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 40,000
FHLB, year of maturity	2029
Number of FHLB advances \| Advance	1
FHLB, interest rate	1.02%
Long Term Debt Maturing 2029 [Member] \| Federal Home Loan Bank, Chicago Advances [Member] \| Long Term FHLB maturing 2029 [Member]
Debt Instruments [Abstract]
Long-term borrowings	$ 165,000	$ 165,000
Weighted average rate	1.61%	1.61%

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Discloses the year of maturity, when only one maturity date applies. for the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

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Discloses the single interest rate [if] applicable to the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Number of Federal Home Loan Bank (FHLB) advances.

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Number of advances in a short term-borrowings.

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The percentage of carrying value of qualifying home equity loans related to limitation on Federal Home Loan Bank borrowings during the period.

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The percentage of carrying value of qualifying one-to-four-family loans related to limitation on Federal Home Loan Bank borrowings during the period.

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