CORPORATE STRUCTURE (Details)	12 Months Ended
Dec. 31, 2015
Georgetown Bancorp, MHC
Conversion and reorganization to stock holding company
Second Step Exchange Ratio	0.72014

In connection with the corporate restructuring, represents the second-step exchange ratio used to convert all share and per share amounts in the consolidated statements of comprehensive income and the notes to consolidated financial statements giving retroactive recognition.

No definition available.

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Namespace Prefix:	gtwn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration