XML 86 R73.htm IDEA: XBRL DOCUMENT
v3.20.4

Variable Interest Entities (Details 2) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 USD ($) trust | Dec. 31, 2019 USD ($)
Variable Interest Entities |  |  |
Number of trusts sponsored | trust |  | 1 |
Percentage of ownership interest |  | 100.00% |
Subordinated notes |  |  |
Amount of subordinated notes |  | $ 58,764 | $ 58,764
June 2007 issuance |  |  |
Subordinated notes |  |  |
Amount of subordinated notes |  | $ 41,238 |
Interest Rate (as a percent) | [1] | 7.22% |
Maturity date of subordinated notes |  | Jun. 15, 2037 |
August 2007 issuance |  |  |
Subordinated notes |  |  |
Amount of subordinated notes |  | $ 17,526 |
Interest Rate (as a percent) | [2] | 1.70% |
Maturity date of subordinated notes |  | Sep. 15, 2037 |
London Interbank Offered Rate (LIBOR) | August 2007 issuance |  |  |
Subordinated notes |  |  |
Basis Spread on Variable Rate (as a percent) |  | 1.48% |
[1] | Fixed rate through life of debt.
[2] | 3-Month LIBOR +1.48% through remaining life of debt.

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: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition -- None. No documentation exists for this element. -- + References No definition available. + Details
Name: | source_VariableInterestEntities
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: | num: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 http://asc.fasb.org/extlink&oid=120400017&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 http://asc.fasb.org/extlink&oid=120398452&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: | num: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: |