XML 63 R52.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Variable Interest Entities (Details 2) $ in Thousands | 9 Months Ended |
--- | --- | ---
Sep. 30, 2022 USD ($) trust | Dec. 31, 2021 USD ($)
Variable Interest Entities [Abstract] |  |
Number of trusts sponsored | trust | 1 |
Percentage of ownership interest | 100.00% |
Subordinated Borrowing [Line Items] |  |
Amount of subordinated notes | $ 58,764 | $ 58,764
June 2007 issuance |  |
Subordinated Borrowing [Line Items] |  |
Amount of subordinated notes | $ 41,238 |
Interest rate (as a percent) | 7.22% |
Maturity date of subordinated notes | Jun. 15, 2037 |
August 2007 issuance |  |
Subordinated Borrowing [Line Items] |  |
Amount of subordinated notes | $ 17,526 |
Interest rate (as a percent) | 4.77% |
Maturity date of subordinated notes | Sep. 15, 2037 |
London Interbank Offered Rate (LIBOR) | August 2007 issuance |  |
Subordinated Borrowing [Line Items] |  |
Basis spread on variable rate (as a percent) | 1.48% |

X
- Definition Maturity date of junior subordinated long-term debt owed to unconsolidated subsidiary trusts. + References No definition available. + Details
Name: | source_MaturityDateOfJuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust
Namespace Prefix: | source_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of trusts sponsored by the entity. + References No definition available. + Details
Name: | source_NumberOfTrustsSponsored
Namespace Prefix: | source_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of ownership interest of common stock or equity participation held by a shareholder of the entity. + References No definition available. + Details
Name: | source_OwnershipPercentage
Namespace Prefix: | source_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Variable Interest Entities [Abstract] + References No definition available. + Details
Name: | source_VariableInterestEntitiesAbstract
Namespace Prefix: | source_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878 + Details
Name: | us-gaap_JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Stated interest rate of the subordinated debt. + References No definition available. + Details
Name: | us-gaap_SubordinatedBorrowingInterestRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_SubordinatedBorrowingLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubordinatedBorrowingAxis=source_SubordinatedNoteIssuedinJune2007Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubordinatedBorrowingAxis=source_SubordinatedNoteIssuedinAugust2007Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |