Represents the capitalization rate used as an unobservable input to measure the fair value.

No definition available.

Name:	gty_CapitalizationRateUnobservableInputs
Namespace Prefix:	gty_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the discount rate used as an unobservable input to measure the fair value.

+ References

No definition available.

+ Details

Name:	gty_DiscountRateUnobservableInputs
Namespace Prefix:	gty_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the impaired net lease assets as of the end of the reporting period that are valued by the entity at fair value as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	gty_ImpairedNetLeaseAssetsFairValueDisclosure
Namespace Prefix:	gty_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the maximum number of years in the assumed holding period used as an unobservable input to measure the fair value.

+ References

No definition available.

+ Details

Name:	gty_MaximumAssumedHoldingPeriodUnobservableInputs
Namespace Prefix:	gty_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the maximum percentage of annual assumed average rent increases used as an unobservable input to measure the fair value.

+ References

No definition available.

+ Details

Name:	gty_MaximumPercentageAnnualAssumedAverageRentIncreasesUnobservableInputs
Namespace Prefix:	gty_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Net Carrying Value Of Properties Marketed For Sale And Classified In Real Estate Held For Sale

+ References

No definition available.

+ Details

Name:	gty_NetCarryingValueOfPropertiesMarketedForSaleAndClassifiedInRealEstateHeldForSale
Namespace Prefix:	gty_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number Of Properties Classified As Held For Sale

+ References

No definition available.

+ Details

Name:	gty_NumberOfPropertiesClassifiedAsHeldForSale
Namespace Prefix:	gty_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	gty_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ordinary taxable income that is required to be distributed to shareholders each year in order to continue to qualify for taxation as a Real Estate Investment Trust.

+ References

No definition available.

+ Details

Name:	gty_PercentageOfOrdinaryTaxableIncomeToShareholders
Namespace Prefix:	gty_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 144

-Paragraph 45, 46, 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2420-110228

+ Details

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

GENERAL - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
GENERAL - Additional Information (Detail) (USD $)	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Property	Sep. 30, 2011	Dec. 31, 2011
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Percentage of ordinary taxable income to shareholders			90.00%
Impairment charges on real estate assets	$ 9,673,000		$ 9,673,000		$ 19,214,000
Number of real estate properties held held for sale			133
Real estate held for sale, net	23,718,000		23,718,000
Impairment charges	$ 7,406,000	$ 587,000	$ 10,552,000	$ 3,094,000
Assumed holding periods for unobservable inputs			15 years
Assumed annual average rent for unobservable inputs			2.00%
Rate of income capitalization for unobservable inputs			8.00%
Cash flows discounted rate for unobservable inputs			7.00%