XML 36 R24.htm IDEA: XBRL DOCUMENT
v3.21.2

Securities (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2021
Securities |
Schedule of amortized cost and fair value of the securities portfolio and corresponding amounts of gross unrealized gains and losses recognized in accumulated other comprehensive loss | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
September 30, 2021 |  | Cost1 |  | Gains |  | Losses | ​ | Value
Securities available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury | ​ | $ | 4,017 | ​ | $ | 53 | ​ | $ | - | ​ | $ | 4,070
U.S. government agencies | ​ | ​ | 33,915 | ​ | ​ | - | ​ | ​ | (340) | ​ | ​ | 33,575
U.S. government agencies mortgage-backed | ​ | ​ | 17,269 | ​ | ​ | 764 | ​ | ​ | (215) | ​ | ​ | 17,818
States and political subdivisions | ​ | ​ | 222,833 | ​ | ​ | 16,758 | ​ | ​ | (639) | ​ | ​ | 238,952
Corporate bonds | ​ | ​ | 5,000 | ​ | ​ | - | ​ | ​ | (8) | ​ | ​ | 4,992
Collateralized mortgage obligations | ​ | ​ | 163,756 | ​ | ​ | 1,966 | ​ | ​ | (308) | ​ | ​ | 165,414
Asset-backed securities | ​ | ​ | 187,825 | ​ | ​ | 1,646 | ​ | ​ | (133) | ​ | ​ | 189,338
Collateralized loan obligations | ​ | ​ | 61,085 | ​ | ​ | 18 | ​ | ​ | (74) | ​ | ​ | 61,029
Total securities available-for-sale | ​ | $ | 695,700 | ​ | $ | 21,205 | ​ | $ | (1,717) | ​ | $ | 715,188
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ ​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
December 31, 2020 |  | Cost1 |  | Gains |  | Losses | ​ | Value
Securities available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury | ​ | $ | 4,014 | ​ | $ | 103 | ​ | $ | - | ​ | $ | 4,117
U.S. government agencies | ​ | ​ | 6,811 | ​ | ​ | - | ​ | ​ | (154) | ​ | ​ | 6,657
U.S. government agencies mortgage-backed | ​ | ​ | 16,098 | ​ | ​ | 1,112 | ​ | ​ | (1) | ​ | ​ | 17,209
States and political subdivisions | ​ | ​ | 229,352 | ​ | ​ | 21,269 | ​ | ​ | (1,362) | ​ | ​ | 249,259
Collateralized mortgage obligations | ​ | ​ | 53,999 | ​ | ​ | 2,866 | ​ | ​ | (280) | ​ | ​ | 56,585
Asset-backed securities | ​ | ​ | 130,959 | ​ | ​ | 1,370 | ​ | ​ | (511) | ​ | ​ | 131,818
Collateralized loan obligations | ​ | ​ | 30,728 | ​ | ​ | 15 | ​ | ​ | (210) | ​ | ​ | 30,533
Total securities available-for-sale | ​ | $ | 471,961 | ​ | $ | 26,735 | ​ | $ | (2,518) | ​ | $ | 496,178
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ 1 Excludes accrued interest receivable of $2.8 million and $2.7 million at September 30, 2021 and December 31, 2020, respectively, that is recorded in other assets on the consolidated balance sheet.
Schedule of fair value, amortized cost and weighted average yield of debt securities by contractual maturity along with securities not due at a single maturity date, primarily mortgage-backed securities (MBS), asset-backed securities, and collateralized loan obligations | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Weighted | ​ | ​ | ​ | ​ | ​
​ | ​ | Amortized | ​ | Average | ​ | ​ | Fair | ​
Securities available-for-sale |  | Cost |  | Yield | ​ |  | Value |
Due in one year or less | ​ | $ | 4,227 | ​ | 1.87 | % | ​ | $ | 4,281 | ​
Due after one year through five years | ​ | ​ | 36,288 | ​ | 0.79 | ​ | ​ | ​ | 36,240 | ​
Due after five years through ten years | ​ | ​ | 28,159 | ​ | 2.35 | ​ | ​ | ​ | 29,387 | ​
Due after ten years | ​ | ​ | 197,091 | ​ | 3.01 | ​ | ​ | ​ | 211,681 | ​
​ | ​ | ​ | 265,765 | ​ | 2.62 | ​ | ​ | ​ | 281,589 | ​
Mortgage-backed and collateralized mortgage obligations | ​ | ​ | 181,025 | ​ | 1.73 | ​ | ​ | ​ | 183,232 | ​
Asset-backed securities | ​ | ​ | 187,825 | ​ | 1.14 | ​ | ​ | ​ | 189,338 | ​
Collateralized loan obligations | ​ | ​ | 61,085 | ​ | 1.40 | ​ | ​ | ​ | 61,029 | ​
Total securities available-for-sale | ​ | $ | 695,700 | ​ | 1.88 | % | ​ | $ | 715,188 | ​
Schedule of amortized cost and fair value of securities that exceed 10% of stockholders equity | At September 30, 2021, the Company had invested in securities issued from one originator that individually amounted to over 10% of the Company’s stockholders’ equity. Information regarding this issuer and the value of the securities issued follows: ​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | September 30, 2021
​ |  | Amortized |  | Fair
Issuer | ​ | Cost | ​ | Value
Towd Point Mortgage Trust | ​ | $ | 32,836 | ​ | $ | 34,339
Schedule of securities with unrealized losses aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Less than 12 months | ​ | 12 months or more | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
September 30, 2021 | ​ | in an unrealized loss position | ​ | in an unrealized loss position | ​ | Total
​ | ​ | Number of | ​ | Unrealized | ​ | Fair | ​ | Number of | ​ | Unrealized | ​ | Fair | ​ | Number of | ​ | Unrealized | ​ | Fair
Securities available-for-sale |  | Securities |  | Losses |  | Value |  | Securities |  | Losses |  | Value |  | Securities |  | Losses |  | Value
U.S. government agencies | ​ | 2 | ​ | $ | 229 | ​ | $ | 28,066 | ​ | 4 | ​ | $ | 111 | ​ | $ | 5,509 | ​ | 6 | ​ | $ | 340 | ​ | $ | 33,575
U.S. government agencies mortgage-backed | ​ | 6 | ​ | ​ | 215 | ​ | ​ | 6,084 | ​ | - | ​ | ​ | - | ​ | ​ | - | ​ | 6 | ​ | ​ | 215 | ​ | ​ | 6,084
States and political subdivisions | ​ | 2 | ​ | ​ | 23 | ​ | ​ | 1,490 | ​ | 1 | ​ | ​ | 616 | ​ | ​ | 4,085 | ​ | 3 | ​ | ​ | 639 | ​ | ​ | 5,575
Corporate bonds | ​ | 1 | ​ | ​ | 8 | ​ | ​ | 4,992 | ​ | - | ​ | ​ | - | ​ | ​ | - | ​ | 1 | ​ | ​ | 8 | ​ | ​ | 4,992
Collateralized mortgage obligations | ​ | 7 | ​ | ​ | 244 | ​ | ​ | 63,495 | ​ | 1 | ​ | ​ | 64 | ​ | ​ | 7,531 | ​ | 8 | ​ | ​ | 308 | ​ | ​ | 71,026
Asset-backed securities | ​ | 5 | ​ | ​ | 79 | ​ | ​ | 35,048 | ​ | 1 | ​ | ​ | 54 | ​ | ​ | 3,270 | ​ | 6 | ​ | ​ | 133 | ​ | ​ | 38,318
Collateralized loan obligations | ​ | 6 | ​ | ​ | 27 | ​ | ​ | 20,386 | ​ | 2 | ​ | ​ | 47 | ​ | ​ | 10,625 | ​ | 8 | ​ | ​ | 74 | ​ | ​ | 31,011
Total securities available-for-sale | ​ | 29 | ​ | $ | 825 | ​ | $ | 159,561 | ​ | 9 | ​ | $ | 892 | ​ | $ | 31,020 | ​ | 38 | ​ | $ | 1,717 | ​ | $ | 190,581
​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Less than 12 months | ​ | 12 months or more | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
December 31, 2020 | ​ | in an unrealized loss position | ​ | in an unrealized loss position | ​ | Total
​ | ​ | Number of | ​ | Unrealized | ​ | ​ | Fair | ​ | Number of | ​ | Unrealized | ​ | ​ | Fair | ​ | Number of | ​ | Unrealized | ​ | ​ | Fair
Securities available-for-sale |  | Securities |  | Losses |  | ​ | Value |  | Securities |  | Losses |  | ​ | Value |  | Securities |  | Losses |  | ​ | Value
U.S. government agencies | ​ | - | ​ | $ | - | ​ | $ | - | ​ | 4 | ​ | $ | 154 | ​ | $ | 6,657 | ​ | 4 | ​ | $ | 154 | ​ | $ | 6,657
U.S. government agencies mortgage-backed | ​ | 1 | ​ | ​ | 1 | ​ | ​ | 141 | ​ | - | ​ | ​ | - | ​ | ​ | - | ​ | 1 | ​ | ​ | 1 | ​ | ​ | 141
States and political subdivisions | ​ | - | ​ | ​ | - | ​ | ​ | - | ​ | 1 | ​ | ​ | 1,362 | ​ | ​ | 3,433 | ​ | 1 | ​ | ​ | 1,362 | ​ | ​ | 3,433
Collateralized mortgage obligations | ​ | 4 | ​ | ​ | 279 | ​ | ​ | 8,142 | ​ | 1 | ​ | ​ | 1 | ​ | ​ | 146 | ​ | 5 | ​ | ​ | 280 | ​ | ​ | 8,288
Asset-backed securities | ​ | 1 | ​ | ​ | 2 | ​ | ​ | 251 | ​ | 3 | ​ | ​ | 509 | ​ | ​ | 49,572 | ​ | 4 | ​ | ​ | 511 | ​ | ​ | 49,823
Collateralized loan obligations | ​ | 1 | ​ | ​ | 31 | ​ | ​ | 7,468 | ​ | 4 | ​ | ​ | 179 | ​ | ​ | 21,477 | ​ | 5 | ​ | ​ | 210 | ​ | ​ | 28,945
Total securities available-for-sale | ​ | 7 | ​ | $ | 313 | ​ | $ | 16,002 | ​ | 13 | ​ | $ | 2,205 | ​ | $ | 81,285 | ​ | 20 | ​ | $ | 2,518 | ​ | $ | 97,287
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Schedule of proceeds from sale and gross realized gains and losses on sale of securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | Three Months Ended | ​ | ​ | Nine Months Ended | ​ | ​
​ | ​ | ​ | September 30, | ​ | ​ | September 30, | ​ | ​
Securities available-for-sale |  | 2021 |  | 2020 |  | 2021 |  | 2020 |  | ​
Proceeds from sales of securities | ​ | $ | 26,873 | ​ | $ | - | ​ | $ | 35,075 | ​ | $ | 18,006 | ​ | ​
Gross realized gains on securities | ​ | $ | 262 | ​ | $ | - | ​ | $ | 267 | ​ | $ | 17 | ​ | ​
Gross realized losses on securities | ​ |  | (18) | ​ |  | (1) | ​ |  | (21) | ​ |  | (42) | ​ | ​
Net realized gains (losses) | ​ | $ | 244 | ​ | $ | (1) | ​ | $ | 246 | ​ | $ | (25) | ​ | ​
Income tax (expense) benefit on net realized gains (losses) | ​ | $ | (69) | ​ | $ | - | ​ | $ | (70) | ​ | $ | 7 | ​ | ​
Effective tax rate applied | ​ | ​ | 28.3 | % | ​ | 0.0 | % | ​ | 28.5 | % | ​ | 28.0 | % | ​

X
- Definition Tabular disclosure of amortized cost and fair value of securities that exceed 10% of stockholders equity. + References No definition available. + Details
Name: | osbc_ScheduleOfAmortizedCostAndFairValueOfSecuritiesThatExceedTenPercentOfStockholdersEquityTableTextBlock
Namespace Prefix: | osbc_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the reconciliation of available-for-sale securities and held-to-maturity securities from cost basis to fair value. + References No definition available. + Details
Name: | osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock
Namespace Prefix: | osbc_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of maturities of an entity's investments as well as any other information pertinent to the investments. + References No definition available. + Details
Name: | us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Tabular disclosure of the proceeds from sales of available-for-sale securities and the gross realized gains and gross realized losses that have been included in earnings as a result of those sales. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27357-111563 + Details
Name: | us-gaap_ScheduleOfRealizedGainLossTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition For all investments in an unrealized loss position, including those for which other-than-temporary impairments have not been recognized in earnings (including investments for which a portion of an other-than-temporary impairment has been recognized in other comprehensive income), a tabular disclosure of the aggregate related fair value of investments with unrealized losses and the aggregate amount of unrealized losses (that is, the amount by which amortized cost basis exceeds fair value). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27290-111563 + Details
Name: | us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration