XML 52 R35.htm IDEA: XBRL DOCUMENT
v3.20.4

Deposits (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Deposits |
Schedule of major classifications of deposits | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | 2020 |  | 2019 |
Noninterest bearing demand | ​ | $ | 909,505 | ​ | $ | 669,795 | ​
Savings | ​ | ​ | 399,057 | ​ | ​ | 307,015 | ​
NOW accounts | ​ | ​ | 486,612 | ​ | ​ | 425,792 | ​
Money market accounts | ​ | ​ | 316,465 | ​ | ​ | 282,478 | ​
Certificates of deposit of less than $100,000 | ​ | ​ | 200,107 | ​ | ​ | 227,578 | ​
Certificates of deposit of $100,000 through $250,000 | ​ | ​ | 164,982 | ​ | ​ | 151,279 | ​
Certificates of deposit of more than $250,000 | ​ | ​ | 60,345 | ​ | ​ | 62,812 | ​
Total deposits | ​ | $ | 2,537,073 | ​ | $ | 2,126,749 | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Summary of scheduled maturities of time deposits | ​
​ | ​ | ​ | ​ | ​
2021 |  | $ | 349,003 | ​
2022 | ​ |  | 30,295 | ​
2023 | ​ |  | 18,308 | ​
2024 | ​ |  | 7,774 | ​
2025 | ​ |  | 20,054 | ​
Total time deposits | ​ | $ | 425,434 | ​

X
- Definition Tabular disclosure of different types of deposits liabilities held by the entity. + References No definition available. + Details
Name: | osbc_ScheduleOfDepositsTableTextBlock
Namespace Prefix: | osbc_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the aggregate amount of maturities for time deposits for each of the five years following the date of the latest fiscal year presented. + References No definition available. + Details
Name: | osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock
Namespace Prefix: | osbc_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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