DEPOSITS (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Time Deposits, Fiscal Year Maturity [Abstract]
1 year or less	$ 462,506,000us-gaap_TimeDepositMaturitiesYearOne	$ 559,402,000us-gaap_TimeDepositMaturitiesYearOne
Over 1 year to 2 years	102,385,000us-gaap_TimeDepositMaturitiesYearTwo	87,645,000us-gaap_TimeDepositMaturitiesYearTwo
Over 2 years to 3 years	29,044,000us-gaap_TimeDepositMaturitiesYearThree	51,778,000us-gaap_TimeDepositMaturitiesYearThree
Over 3 years to 4 years	26,156,000us-gaap_TimeDepositMaturitiesYearFour	20,462,000us-gaap_TimeDepositMaturitiesYearFour
Over 4 years to 5 years	29,529,000us-gaap_TimeDepositMaturitiesYearFive	24,288,000us-gaap_TimeDepositMaturitiesYearFive
Over 5 years	0	53,000
Time Deposits	649,620,000us-gaap_TimeDeposits	743,628,000us-gaap_TimeDeposits
1 year or less (as percent)	71.20%	75.10%
Over 1 years to 2 years (as percent)	15.80%	11.80%
Over 2 years to 3 years (as percent)	4.50%	7.00%
Over 3 years to 4 years (as percent)	4.00%	2.80%
Over 4 years to 5 years (as percent)	4.50%	3.30%
Over 5 years (as percent)	0.00%	0.00%
Time Deposits (as percent)	100.00%indb_TimeDepositsPercentOfTotal	100.00%indb_TimeDepositsPercentOfTotal
Overdraft deposits reclassified to the loan category	$ 3,500,000	$ 2,400,000

Time Deposit Maturities, after Year Five, Percent of Total

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- Definition

Time Deposit Maturities, Next Twelve Months, Percent of Total

+ References

No definition available.

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- Definition

Time Deposit Maturities, Year Five, Percent of Total

+ References

No definition available.

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- Definition

Time Deposit Maturities, Year Four, Percent of Total

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No definition available.

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- Definition

Time Deposit Maturities, Year Three, Percent of Total

+ References

No definition available.

+ Details

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- Definition

Time Deposit Maturities, Year Two, Percent of Total

+ References

No definition available.

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- Definition

Time Deposits, Percent of Total

+ References

No definition available.

+ Details

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- Definition

Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 405

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6479006&loc=d3e64164-112818

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- Definition

Amount of time deposits maturing after the fifth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

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Amount of time deposits maturing in the fifth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of time deposits maturing in the fourth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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Amount of time deposits maturing in the next fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the third fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the second fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

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