Summary of Significant Accounting Policies - Tenant Accounts Receivable (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Tenant Accounts Receivable, net
Allowance for doubtful accounts	$ 0.3	$ 0.1
Accrued rental revenue	14.1stag_AccruedRentalRevenue	12.8stag_AccruedRentalRevenue
Allowance on accrued rental revenue	0.1stag_AllowanceOnAccruedRentalRevenue	0stag_AllowanceOnAccruedRentalRevenue
Lease security deposits available in existing letters of credit	6.3	6.7
Lease security deposits available in cash	$ 3.5	$ 3.5

Represents the amount of rental revenue accrued as of balance sheet date.

No definition available.

Name:	stag_AccruedRentalRevenue
Namespace Prefix:	stag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the amount of allowance on accrued rental revenue as of balance sheet date.

+ References

No definition available.

+ Details

Name:	stag_AllowanceOnAccruedRentalRevenue
Namespace Prefix:	stag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the amount of lease security deposit received by the entity, available in cash.

+ References

No definition available.

+ Details

Name:	stag_LeaseSecurityDepositsAvailableInCash
Namespace Prefix:	stag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the amount of lease security deposit received by the entity, available in letters of credit.

+ References

No definition available.

+ Details

Name:	stag_LeaseSecurityDepositsAvailableInLettersOfCredit
Namespace Prefix:	stag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Definition

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 4

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.4)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant