XML 24 R14.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Equity Securities Without Readily Determinable Fair Values | 3 Months Ended
--- | ---
Mar. 31, 2018
Equity Method And Other Investments [Abstract] |
Equity Securities Without Readily Determinable Fair Values | Equity Securities Without Readily Determinable Fair Values Included in equity securities without readily determinable fair values are restricted securities, which are carried at cost, and investments in unconsolidated entities accounted for under the equity method of accounting. Equity securities without readily determinable fair values consist of the following as of:
| March 31 2018 |  | December 31 2017
FHLB Stock | $ | 13,700 |  |  | $ | 13,700 |
Corporate Settlement Solutions, LLC | 7,358 |  |  | 7,421 |
FRB Stock | 1,999 |  |  | 1,999 |
Other | 334 |  |  | 334 |
Total | $ | 23,391 |  |  | $ | 23,454 |

X
- Definition Equity Method And Other Investments [Abstract] + References No definition available. + Details
Name: | isba_EquityMethodAndOtherInvestmentsAbstract
Namespace Prefix: | isba_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Equity Method And Other Investments [Text Block] + References No definition available. + Details
Name: | isba_EquityMethodAndOtherInvestmentsTextBlock
Namespace Prefix: | isba_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration