Business Acquisition, Cost of Acquired Entity, Percentage Cash Paid

No definition available.

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- Definition

Business Acquisition, Cost of Acquired Entity, Percentage Stock Consideration

+ References

No definition available.

+ Details

Name:	indb_BusinessAcquisitionCostOfAcquiredEntityPercentageStockConsideration
Namespace Prefix:	indb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Business Acquisition, Equity Interest Issued or Issuable, Number of Shares of Company Stock Issued for Each Share of Acquiree Stock

+ References

No definition available.

+ Details

Name:	indb_BusinessAcquisitionEquityInterestIssuedOrIssuableNumberOfSharesOfCompanyStockIssuedForEachShareOfAcquireeStock
Namespace Prefix:	indb_
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Balance Type:	na
Period Type:	instant

- Definition

Business Acquisition, Equity Interest Issued or Issuable Shareholders Option To Receive, Cash Per Share

+ References

No definition available.

+ Details

Name:	indb_BusinessAcquisitionEquityInterestIssuedOrIssuableShareholdersOptionToReceiveCashPerShare
Namespace Prefix:	indb_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition.

+ References

No definition available.

+ Details

Name:	indb_BusinessCombinationCostofAcquiredEntityPurchasePrice
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Business Combination, Fair Value of Shareholders Option To Receive, Per Share

+ References

No definition available.

+ Details

Name:	indb_BusinessCombinationFairValueofShareholdersOptionToReceivePerShare
Namespace Prefix:	indb_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Business Combination, Increase in Acquirer Outstanding Shares

+ References

No definition available.

+ Details

Name:	indb_BusinessCombinationIncreaseInAcquirerOutstandingShares
Namespace Prefix:	indb_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 23

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e1043-128460

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

+ 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 210.9-03.16)

-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 16

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-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=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 10

-Section F

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Article 5

-Subsection 19, 20, 22

+ Details

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- Details

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- Details

Name:	us-gaap_BusinessAcquisitionAxis=indb_PeoplesFederalBancsharesIncMember
Namespace Prefix:
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Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SubordinatedDebtMember
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Subsequent Events (Details) (USD $)	3 Months Ended							12 Months Ended			0 Months Ended
Subsequent Events (Details) (USD $)	Dec. 31, 2014	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 20, 2015
Subsequent Event [Line Items]
Acquisition Related Costs	$ 586,000	$ 677,000	$ 77,000	$ 6,219,000	$ 366,000	$ 754,000	$ 1,345,000	$ 1,339,000	$ 8,685,000	$ 6,741,000
Subordinated Debt	65,000,000us-gaap_SubordinatedDebt			30,000,000us-gaap_SubordinatedDebt				65,000,000us-gaap_SubordinatedDebt	30,000,000us-gaap_SubordinatedDebt
Peoples Federal Bancshares, Inc [Member]
Subsequent Event [Line Items]
Acquisition Related Costs								1,300,000
Peoples Federal Bancshares, Inc [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Interest Issued or Issuable Shareholders Option To Receive, Cash Per Share											$ 21.00
Number of shares of company stock issued for each share of Central common stock (in shares)											0.552
Fair Value of Shareholders Option To Receive (usd per share)											$ 23.26
Share Price (usd per share)											$ 42.11
Business transaction value											141,800,000
Cost of acquired entity, percentage cash											40.00%
Cost of Acquired Entity, Percentage Stock Consideration											60.00%
Cost of acquired entity, cash paid											55,400,000
Consideration Transferred, Equity Interests Issued and Issuable											86,400,000
Increase in acquirer outstanding shares											2,052,137
Subordinated Debt [Member]
Subsequent Event [Line Items]
Subordinated Debt	$ 30,000,000							$ 30,000,000
Debt Instrument term								5 years
Subordinated Debt [Member] \| LIBOR [Member]
Subsequent Event [Line Items]
Basis spread on variable rate								3.00%