XML 61 R45.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Fair Value Measurements (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2023
Fair Value Measurements |
Schedule of balance of assets and liabilities which are measured at fair value on a recurring basis | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2023
​ |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Assets: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Securities available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury | ​ | $ | 169,574 | ​ | $ | - | ​ | $ | - | ​ | $ | 169,574
U.S. government agencies | ​ | ​ | - | ​ | ​ | 56,959 | ​ | ​ | - | ​ | ​ | 56,959
U.S. government agencies mortgage-backed | ​ | ​ | - | ​ | ​ | 106,370 | ​ | ​ | - | ​ | ​ | 106,370
States and political subdivisions | ​ | ​ | - | ​ | ​ | 214,006 | ​ | ​ | 15,329 | ​ | ​ | 229,335
Collateralized mortgage obligations | ​ | ​ | - | ​ | ​ | 392,544 | ​ | ​ | - | ​ | ​ | 392,544
Asset-backed securities | ​ | ​ | - | ​ | ​ | 66,166 | ​ | ​ | - | ​ | ​ | 66,166
Collateralized loan obligations | ​ | ​ | - | ​ | ​ | 171,881 | ​ | ​ | - | ​ | ​ | 171,881
Loans held-for-sale | ​ | ​ | - | ​ | ​ | 1,322 | ​ | ​ | - | ​ | ​ | 1,322
Mortgage servicing rights | ​ | ​ | - | ​ | ​ | - | ​ | ​ | 10,344 | ​ | ​ | 10,344
Interest rate swap agreements, including risk participation agreement | ​ | ​ | - | ​ | ​ | 5,391 | ​ | ​ | - | ​ | ​ | 5,391
Mortgage banking derivatives | ​ | ​ | - | ​ | ​ | (10) | ​ | ​ | - | ​ | ​ | (10)
Total | ​ | $ | 169,574 | ​ | $ | 1,014,629 | ​ | $ | 25,673 | ​ | $ | 1,209,876
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Liabilities: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Interest rate swap agreements, including risk participation agreements | ​ | $ | - | ​ | $ | 8,324 | ​ | $ | - | ​ | $ | 8,324
Total | ​ | $ | - | ​ | $ | 8,324 | ​ | $ | - | ​ | $ | 8,324
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2022
​ |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Assets: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Securities available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury | ​ | $ | 212,129 | ​ | $ | - | ​ | $ | - | ​ | $ | 212,129
U.S. government agencies | ​ | ​ | - | ​ | ​ | 56,048 | ​ | ​ | - | ​ | ​ | 56,048
U.S. government agencies mortgage-backed | ​ | ​ | - | ​ | ​ | 124,990 | ​ | ​ | - | ​ | ​ | 124,990
States and political subdivisions | ​ | ​ | - | ​ | ​ | 211,899 | ​ | ​ | 14,229 | ​ | ​ | 226,128
Corporate bonds | ​ | ​ | - | ​ | ​ | 9,622 | ​ | ​ | - | ​ | ​ | 9,622
Collateralized mortgage obligations | ​ | ​ | - | ​ | ​ | 526,998 | ​ | ​ | 6,770 | ​ | ​ | 533,768
Asset-backed securities | ​ | ​ | - | ​ | ​ | 186,916 | ​ | ​ | 15,012 | ​ | ​ | 201,928
Collateralized loan obligations | ​ | ​ | - | ​ | ​ | 174,746 | ​ | ​ | - | ​ | ​ | 174,746
Loans held-for-sale | ​ | ​ | - | ​ | ​ | 491 | ​ | ​ | - | ​ | ​ | 491
Mortgage servicing rights | ​ | ​ | - | ​ | ​ | - | ​ | ​ | 11,189 | ​ | ​ | 11,189
Interest rate swap agreements | ​ | ​ | - | ​ | ​ | 6,516 | ​ | ​ | - | ​ | ​ | 6,516
Mortgage banking derivatives | ​ | ​ | - | ​ | ​ | 76 | ​ | ​ | - | ​ | ​ | 76
Total | ​ | $ | 212,129 | ​ | $ | 1,298,302 | ​ | $ | 47,200 | ​ | $ | 1,557,631
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Liabilities: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Interest rate swap agreements, including risk participation agreements | ​ | $ | - | ​ | $ | 12,265 | ​ | $ | - | ​ | $ | 12,265
Total | ​ | $ | - | ​ | $ | 12,265 | ​ | $ | - | ​ | $ | 12,265
Schedule of changes in Level 3 assets and liabilities measured at fair value on a recurring basis | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended December 31, 2023
​ | ​ | Securities available-for-sale | ​ | ​ | ​
​ | ​ | ​ | Collateralized | States and | ​ | Mortgage
​ | ​ | Asset-backed | Mortgage | Political | ​ | Servicing
​ |  | Securities | Obligations | Subdivisions |  | Rights
Beginning balance January 1, 2023 | ​ | $ | 15,012 | $ | 6,770 | $ | 14,229 | ​ | $ | 11,189
Transfers out of Level 3 | ​ | ​ | (14,885) | ​ | (6,764) | ​ | - | ​ | ​ | -
Total gains or losses | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Included in earnings | ​ | ​ | (11) | ​ | - | ​ | (134) | ​ | ​ | (924)
Included in other comprehensive income | ​ | ​ | 226 | ​ | (6) | ​ | 1,010 | ​ | ​ | -
Purchases, issuances, sales, and settlements | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Purchases | ​ | ​ | - | ​ | - | ​ | 782 | ​ | ​ | -
Issuances | ​ | ​ | - | ​ | - | ​ | - | ​ | ​ | 580
Settlements | ​ | ​ | (342) | ​ | - | ​ | (558) | ​ | ​ | (501)
Ending balance December 31, 2023 | ​ | $ | - | $ | - | $ | 15,329 | ​ | $ | 10,344
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | Year Ended December 31, 2022 | ​
​ | ​ | ​ | Securities available-for-sale | ​ | ​ | ​ | ​
​ | ​ | ​ | Collateralized | States and | ​ | Mortgage | ​
​ | ​ | Asset-backed | Mortgage | Political | ​ | Servicing | ​
​ |  | Securities | Obligations | Subdivisions |  | Rights |
Beginning balance January 1, 2022 | ​ | $ | - | $ | - | $ | 15,236 | ​ | $ | 7,097 | ​
Transfers into Level 3 | ​ | ​ | 15,012 | ​ | 6,770 | ​ | - | ​ | ​ | - | ​
Transfers out of Level 3 | ​ | ​ | - | ​ | - | ​ | - | ​ | ​ | - | ​
Total gains or losses | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Included in earnings | ​ | ​ | - | ​ | - | ​ | (136) | ​ | ​ | 4,106 | ​
Included in other comprehensive income | ​ | ​ | - | ​ | - | ​ | (86) | ​ | ​ | - | ​
Purchases, issuances, sales, and settlements | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Purchases | ​ | ​ | - | ​ | - | ​ | 519 | ​ | ​ | - | ​
Issuances | ​ | ​ | - | ​ | - | ​ | - | ​ | ​ | 915 | ​
Settlements | ​ | ​ | - | ​ | - | ​ | (1,304) | ​ | ​ | (929) | ​
Ending balance December 31, 2022 | ​ | $ | 15,012 | $ | 6,770 | $ | 14,229 | ​ | $ | 11,189 | ​
Schedule of quantitative information about level 3 fair value measurements | The following table and commentary presents quantitative and qualitative information about Level 3 fair value measurements as of December 31, 2023: ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | Weighted
Measured at fair value | ​ | ​ | ​ | ​ | ​ | ​ | Significant Unobservable | ​ | ​ | ​ | Average
on a recurring basis: |  | Fair Value |  | Valuation Methodology |  | Inputs |  | Range of Input |  | of Inputs
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
States and political subdivisions | ​ | $ | 15,329 | ​ | Discounted Cash Flow | ​ | Discount Rate | ​ | 3.2 – 5.6% | ​ | 4.8 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | Liquidity Premium | ​ | 0.0 – 0.5% | ​ | 0.4 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Mortgage servicing rights | ​ | $ | 10,344 | ​ | Discounted Cash Flow | ​ | Discount Rate | ​ | 9.0 – 11.0% | ​ | 9.0 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | Prepayment Speed | ​ | 5.1 – 33.0% | ​ | 6.6 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
The following table and commentary presents quantitative and qualitative information about Level 3 fair value measurements as of December 31, 2022: ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | Weighted
Measured at fair value | ​ | ​ | ​ | ​ | ​ | ​ | Significant Unobservable | ​ | ​ | ​ | Average
on a recurring basis: |  | Fair Value |  | Valuation Methodology |  | Inputs |  | Range of Input |  | of Inputs
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
States and political subdivisions | ​ | $ | 14,229 | ​ | Discounted Cash Flow | ​ | Discount Rate | ​ | 2.3 – 5.8% | ​ | 4.4 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | Liquidity Premium | ​ | 0.3 – 0.5% | ​ | 0.5 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Collateralized mortgage obligations | ​ | $ | 6,770 | ​ | Discounted Cash Flow | ​ | Discount Rate | ​ | 7.0 – 7.0% | ​ | 7.0 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Asset-backed securities | ​ | $ | 15,012 | ​ | Discounted Cash Flow | ​ | Discount Rate | ​ | 6.2 – 6.5% | ​ | 6.3 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Mortgage servicing rights | ​ | $ | 11,189 | ​ | Discounted Cash Flow | ​ | Discount Rate | ​ | 9.0 – 11.0% | ​ | 9.0 | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | Prepayment Speed | ​ | 3.6 – 27.3% | ​ | 6.2 | %
Schedule of assets measured at fair value on a nonrecurring basis | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2023
​ |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Individually evaluated loans1 | ​ | $ | - | ​ | $ | - | ​ | $ | 66,180 | ​ | $ | 66,180
Other real estate owned, net2 | ​ | ​ | - | ​ | ​ | - | ​ | ​ | 5,123 | ​ | ​ | 5,123
Total | ​ | $ | - | ​ | $ | - | ​ | $ | 71,303 | ​ | $ | 71,303
​
1 | Represents carrying value and related write-downs of loans for which adjustments are substantially based on the appraised value of collateral for collateral-dependent loans and to a lesser extent the discounted cash flow, had a carrying amount of $77.3 million and a valuation allowance of $11.1 million, resulting in a decrease of specific allocations within the provision for credit losses of $6.5 million for the year ending December 31, 2023.
​
2 | OREO is measured at the lower of carrying or fair value less costs to sell, and had a net carrying amount of $5.1 million, which is made up of the outstanding balance of $5.2 million, net of a valuation allowance of $118,000 at December 31, 2023.
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2022
​ |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Individually evaluated loans1 | ​ | $ | - | ​ | $ | - | ​ | $ | 47,700 | ​ | $ | 47,700
Other real estate owned, net2 | ​ | ​ | - | ​ | ​ | - | ​ | ​ | 1,561 | ​ | ​ | 1,561
Total | ​ | $ | - | ​ | $ | - | ​ | $ | 49,261 | ​ | $ | 49,261
​
1 | Represents carrying value and related write-downs of loans for which adjustments are substantially based on the appraised value of collateral for collateral-dependent loans and to a lesser extent the discounted cash flow, had a carrying amount of $65.3 million and a valuation allowance of $17.6 million, resulting in an increase of specific allocations within the provision for credit losses of $12.2 million for the year ending December 31, 2022.
​
2 | OREO is measured at the lower of carrying or fair value less costs to sell, and had a net carrying amount of $1.6 million, which is made up of the outstanding balance of $2.5 million, net of a valuation allowance of $856,000 and purchase accounting adjustments of $131,000 at December 31, 2022.

X
- Definition Tabular disclosure of the fair value measurement of assets and liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income, and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset or liability. + References No definition available. + Details
Name: | osbc_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock
Namespace Prefix: | osbc_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of input and valuation technique used to measure fair value and change in valuation approach and technique for each separate class of asset and liability measured on recurring and nonrecurring basis. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb) -SubTopic 10 -Topic 820 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of assets and liabilities by class, including financial instruments measured at fair value that are classified in shareholders' equity, if any, that are measured at fair value on a nonrecurring basis in periods after initial recognition (for example, impaired assets). Disclosures may include, but are not limited to: (a) the fair value measurements recorded and the reasons for the measurements and (b) the level within the fair value hierarchy in which the fair value measurements are categorized in their entirety (levels 1, 2, 3). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb) -SubTopic 10 -Topic 820 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration