Loans, Allowance for Loan Losses and Credit Quality (Post-Modification balance of TDRs Listed by Type of Modifications) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Post modification balance of Troubled Debt Restructuring
EXTENDED MATURITY	$ 1,207	$ 1,195
COMBINATION RATE & MATURITY	0	238
COURT ORDERED CONCESSION	90	0
TOTAL	$ 1,297	$ 1,433

Financing receivable modifications post modification recorded investment combination of rate and maturity.

No definition available.

Name:	indb_FinancingReceivableModificationsPostModificationRecordedInvestmentCombinationOfRateAndMaturity
Namespace Prefix:	indb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration