Annual Dividend Rate Per Share

No definition available.

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Namespace Prefix:	gcbc_
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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the dividend to be paid was declared, in CCYY-MM-DD format.

+ References

+ Details

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- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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Subsequent events (Details) - $ / shares			3 Months Ended
Subsequent events (Details) - $ / shares	Oct. 20, 2015	Jul. 21, 2015	Sep. 30, 2015	Sep. 30, 2014
Subsequent Event [Line Items]
Common stock, dividends, per share, declared (in dollars per share)			$ 0.185	$ 0.180
Dividend Declared in Q1 2016 [Member]
Subsequent Event [Line Items]
Dividends payable, date declared			Oct. 20, 2015
Dividends payable, date of record			Nov. 13, 2015
Dividends payable, date to be paid			Nov. 30, 2015
Dividend Declared 2016 Annual [Member]
Subsequent Event [Line Items]
Common stock, dividends, per share, declared (in dollars per share)		$ 0.74
Subsequent Event [Member] \| Dividend Declared in Q1 2016 [Member]
Subsequent Event [Line Items]
Common stock, dividends, per share, declared (in dollars per share)	$ 0.185
Subsequent Event [Member] \| Dividend Declared 2016 Annual [Member]
Subsequent Event [Line Items]
Annual dividend rate per share (in dollars per share)	$ 0.74