XML 60 R41.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Premises and Equipment (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2024
Premises and Equipment |
Schedule of components of premises and equipment | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | 2024 | ​ | 2023 | ​ | ​
​ |  | ​ | ​ |  | Accumulated |  | ​ | ​ |  | ​ | ​ |  | Accumulated |  | ​ | ​ |  | ​
​ | ​ | ​ | ​ | ​ | Depreciation/ | ​ | Net Book | ​ | ​ | ​ | ​ | Depreciation/ | ​ | Net Book | ​ | ​
​ | ​ | Cost | ​ | Amortization | ​ | Value | ​ | Cost | ​ | Amortization | ​ | Value | ​ | ​
Land | ​ | $ | 30,981 | ​ | $ | - | ​ | $ | 30,981 | ​ | $ | 29,741 | ​ | $ | - | ​ | $ | 29,741 | ​ | ​
Buildings | ​ |  | 61,428 | ​ |  | 27,413 | ​ |  | 34,015 | ​ |  | 58,311 | ​ |  | 25,911 | ​ |  | 32,400 | ​ | ​
Leasehold improvements | ​ |  | 10,341 | ​ |  | 2,112 | ​ |  | 8,229 | ​ |  | 7,785 | ​ |  | 1,574 | ​ |  | 6,211 | ​ | ​
Furniture and equipment | ​ |  | 63,884 | ​ |  | 49,798 | ​ |  | 14,086 | ​ |  | 57,447 | ​ | ​ | 46,489 | ​ |  | 10,958 | ​ | ​
Total Premises and Equipment | ​ | $ | 166,634 | ​ | $ | 79,323 | ​ | $ | 87,311 | ​ | $ | 153,284 | ​ | $ | 73,974 | ​ | $ | 79,310 | ​ | ​
Schedule of Right-of-use asset and lease obligations by type of property | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
December 31, 2024 | ​ | Right-of-Use Asset | ​ | Lease Liability | ​ | Weight Average Lease Term in Years | ​ | Weight Average Discount Rate
Operating Leases | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Land and building leases | ​ | $ | 7,359 | ​ | $ | 12,465 | ​ | ​ | 13.7 | ​ | 4.72 | %
Total operating leases | ​ | $ | 7,359 | ​ | $ | 12,465 | ​ | ​ | 13.7 | ​ | 4.72 | %
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
December 31, 2023 | ​ | Right-of-Use Asset | ​ | Lease Liability | ​ | Weight Average Lease Term in Years | ​ | Weight Average Discount Rate
Operating Leases | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Land and building leases | ​ | $ | 7,093 | ​ | $ | 11,578 | ​ | ​ | 12.5 | ​ | 4.65 | %
Total operating leases | ​ | $ | 7,093 | ​ | $ | 11,578 | ​ | ​ | 12.5 | ​ | 4.65 | %
Schedule of operating lease costs | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | 2024 | ​ | 2023 | ​ | 2022
Operating lease cost | ​ | $ | 1,337 | ​ | $ | 988 | ​ | $ | 716
Short-term lease cost | ​ | ​ | 54 | ​ | ​ | 64 | ​ | ​ | 60
Total operating lease cost | ​ | $ | 1,391 | ​ | $ | 1,052 | ​ | $ | 776
Schedule of maturity analysis of operating lease liabilities and reconciliation of the undiscounted cash flows | A maturity analysis of operating lease liabilities and reconciliation of the undiscounted cash flows to the total operating lease liability as of December 31, 2024, is listed below. ​
​ | ​ | ​ | ​
Lease payments | ​ | ​ | ​
Due in one year or less | ​ | $ | 2,095
Due in one year through two years | ​ | ​ | 1,903
Due in two years through three years | ​ | ​ | 1,847
Due in three years through four years | ​ | ​ | 1,756
Due in four years through five years | ​ | ​ | 1,692
Thereafter | ​ | ​ | 5,824
Total lease payments | ​ | ​ | 15,117
Discount on cash flows | ​ | ​ | (2,652)
Total lease liabilities | ​ | $ | 12,465
​

X
- Definition Tabular disclosure of lessee's operating lease by property. + References No definition available. + Details
Name: | osbc_ScheduleOfLesseeOperatingLeaseByPropertyTableTextBlock
Namespace Prefix: | osbc_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of lessee's lease cost. Includes, but is not limited to, interest expense for finance lease, amortization of right-of-use asset for finance lease, operating lease cost, short-term lease cost, variable lease cost and sublease income. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147478964/842-20-50-4 + Details
Name: | us-gaap_LeaseCostTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of undiscounted cash flows of lessee's operating lease liability. Includes, but is not limited to, reconciliation of undiscounted cash flows to operating lease liability recognized in statement of financial position. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147478964/842-20-50-6 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Tabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -SubTopic 10 -Topic 360 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482099/360-10-50-1 + Details
Name: | us-gaap_PropertyPlantAndEquipmentTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration