Investments is Low Income Housing Tax Credits Investments in Low Income Housing Tax Credits (Textual) (Details) (USD $)	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Investments Schedule [Abstract]
Capital commitment relating to Low Income Housing Project investments	$ 23,278,501	$ 0

Capital commitment relating to Low Income Housing Project investments

No definition available.

Name:	indb_CapitalcommitmentrelatingtoLowIncomeHousingProjectinvestments
Namespace Prefix:	indb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration