Notes Payable and Unsecured Credit Facilities Notes Payable Phantom (Details)	12 Months Ended
Dec. 31, 2015
Variable Income Interest Rate [Member] \| Construction Loans [Member]
Debt Instrument, Interest Rate Terms	1 month LIBOR plus 150 basis points
Unsecured Debt [Member] \| General Loan [Member]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Unsecured Debt [Member] \| Term Loan - Unsecured [Member]
Debt Instrument, Basis Spread on Variable Rate	9.75%
Line of Credit [Member]
Line of Credit Facility, Unsecured, Interest Rate Description	LIBOR plus 0.925 basis points
Line of Credit Facility, Unsecured, Annual Facility Fee	.0015
Line of Credit [Member] \| Line of Credit Facility - Unsecured [Member]
Debt Instrument, Basis Spread on Variable Rate	9.25%
Line of Credit Facility, Commitment Fee Percentage	0.15%
Term Loan - Unsecured [Member]
Debt Instrument, Interest Rate Terms	LIBOR plus 0.975 basis points
Line of Credit Facility, Unsecured, Annual Facility Fee	35

Line of Credit Facility, Annual Fee Description

No definition available.

Name:	reg_LineOfCreditFacilityAnnualFeeDescription
Namespace Prefix:	reg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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

- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_VariableIncomeInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=reg_GeneralLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=reg_TermLoanUnsecuredMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=reg_LineOfCreditFacilityUnsecuredMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=reg_TermLoanUnsecuredMember
Namespace Prefix:
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Balance Type:
Period Type: