Organization and Description of Business (Details) ft² in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2017 ft² tenant state building	Dec. 31, 2016
Real Estate Properties [Line Items]
Ownership interest in Operating Partnership (as a percent)	95.70%	95.70%
Number of properties	342
Number of states in which the entity owned buildings \| state	37
Area (in square feet) \| ft²	67.7
Percentage of buildings leased to tenants	94.00%
Number of tenants \| tenant	296
Warehouse - Distribution buildings
Real Estate Properties [Line Items]
Number of properties	274
Light Manufacturing buildings
Real Estate Properties [Line Items]
Number of properties	53
Flex/Office Buildings
Real Estate Properties [Line Items]
Number of properties	14
Other Property [Member]
Real Estate Properties [Line Items]
Number of properties	1

Represents the number of tenants.

No definition available.

Name:	stag_NumberOfTenants
Namespace Prefix:	stag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Occupancy Percentage of Real Estate Properties

+ References

No definition available.

+ Details

Name:	stag_OccupancyPercentageofRealEstateProperties
Namespace Prefix:	stag_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_WarehouseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_IndustrialPropertyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_OfficeBuildingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_OtherPropertyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: