End date of current fiscal year in the format --MM-DD.

No definition available.

Name:	dei_CurrentFiscalYearEndDate
Namespace Prefix:	dei_
Data Type:	xbrli:gMonthDayItemType
Balance Type:	na
Period Type:	duration

- Definition

This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.

+ References

No definition available.

+ Details

Name:	dei_DocumentFiscalYearFocus
Namespace Prefix:	dei_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Derivative, Early Termination Date

+ References

No definition available.

+ Details

Name:	reg_DerivativeEarlyTerminationDate
Namespace Prefix:	reg_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Unsecured Debt Repayment

+ References

No definition available.

+ Details

Name:	reg_UnsecuredDebtRepayment
Namespace Prefix:	reg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Date the entity entered into the derivative contract, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

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

- Definition

Date the derivative contract matures, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

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

- Definition

Reference to the index or unit of measurement for the underlying which establishes the pricing terms of the derivative instrument. For example, the basis on the underlying for a natural gas futures contract might be the NYMEX price per million British thermal units (MMBtu).

+ References

No definition available.

+ Details

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

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

- Definition

Fair value as of the balance sheet date of all interest rate derivative assets designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624163-113959

+ Details

Name:	us-gaap_InterestRateCashFlowHedgeAssetAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of all interest rate derivatives designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

+ Details

Name:	us-gaap_InterestRateCashFlowHedgeDerivativeAtFairValueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of all interest rate derivative liabilities designated as cash flow hedging instruments.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Details

Name:	us-gaap_DerivativeByNatureAxis=reg_Derivative1.048200KMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeByNatureAxis=us-gaap_AssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeByNatureAxis=reg_Derivative1.07065KMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeByNatureAxis=reg_Derivative2.19628.1KMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeByNatureAxis=reg_Derivative1.3025020.0MMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeByNatureAxis=reg_Derivative1.49033.0MMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeByNatureAxis=reg_Derivative3.48820KMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeByNatureAxis=reg_Derivative3.48100KMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeByNatureAxis=reg_Derivative3.48100K2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
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:	reg_ScheduledPrincipalPaymentsAndMaturitiesAxis=reg_UnsecuredMaturitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative Financial Instruments - Fair Value of Derivatives (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Jul. 13, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Document Fiscal Year Focus	2016
Current Fiscal Year End Date	--12-31
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 91,618,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	62,187,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	$ 125,205,000
Derivative @ 1.048% 200K [Member]
Derivatives, Fair Value [Line Items]
Derivative, Inception Date	Aug. 01, 2016
Derivative, Maturity Date	Jan. 05, 2022
Derivative, Notional Amount	$ 200,000,000
Derivative, Underlying Basis	1 Month LIBOR
Derivative, Fixed Interest Rate	1.0477%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 7,538,000		$ 0
Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 220,000,000
Derivative @ 1.070% 65K [Member]
Derivatives, Fair Value [Line Items]
Derivative, Inception Date	Aug. 01, 2016
Derivative, Maturity Date	Jan. 05, 2022
Derivative, Notional Amount	$ 65,000,000
Derivative, Underlying Basis	1 Month LIBOR
Derivative, Fixed Interest Rate	1.07%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 2,351,000		0
Derivative @ 2.196% 28.1K [Member]
Derivatives, Fair Value [Line Items]
Derivative, Inception Date	Oct. 16, 2013
Derivative, Maturity Date	Oct. 16, 2020
Derivative, Notional Amount	$ 28,100,000
Derivative, Underlying Basis	1 Month LIBOR
Derivative, Fixed Interest Rate	2.196%
Interest Rate Cash Flow Hedge Liability at Fair Value	$ (580,000)		(898,000)
Derivative @ 1.30250% 20.0M [Member]
Derivatives, Fair Value [Line Items]
Derivative, Inception Date	Apr. 07, 2016
Derivative, Maturity Date	Apr. 01, 2023
Derivative, Notional Amount	$ 20,000,000
Derivative, Underlying Basis	1 Month LIBOR
Derivative, Fixed Interest Rate	1.3025%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 720,000		0
Derivative @ 1.490% 33.0M [Member]
Derivatives, Fair Value [Line Items]
Derivative, Inception Date	Dec. 01, 2016
Derivative, Maturity Date	Nov. 01, 2023
Derivative, Notional Amount	$ 33,000,000
Derivative, Underlying Basis	1 Month LIBOR
Derivative, Fixed Interest Rate	1.49%
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 1,013,000		0
Derivative @ 3.488% 20K [Member]
Derivatives, Fair Value [Line Items]
Derivative, Inception Date	Jun. 15, 2017
Derivative, Maturity Date	Jun. 15, 2027
Derivative, Early Termination Date	Dec. 15, 2017
Derivative, Notional Amount	$ 20,000,000
Derivative, Underlying Basis	3 Month LIBOR
Derivative, Fixed Interest Rate	3.4875%
Interest Rate Cash Flow Hedge Liability at Fair Value	$ 0		(1,798,000)
Derivative @ 3.48% 100K [Member]
Derivatives, Fair Value [Line Items]
Derivative, Inception Date	Jun. 15, 2017
Derivative, Maturity Date	Jun. 15, 2027
Derivative, Early Termination Date	Dec. 15, 2017
Derivative, Notional Amount	$ 100,000,000
Derivative, Underlying Basis	3 Month LIBOR
Derivative, Fixed Interest Rate	3.48%
Interest Rate Cash Flow Hedge Liability at Fair Value	$ 0		(8,922,000)
Derivative @ 3.48% 100K 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative, Inception Date	Jun. 15, 2017
Derivative, Maturity Date	Jun. 15, 2027
Derivative, Early Termination Date	Dec. 15, 2017
Derivative, Notional Amount	$ 100,000,000
Derivative, Underlying Basis	3 Month LIBOR
Derivative, Fixed Interest Rate	3.48%
Interest Rate Cash Flow Hedge Liability at Fair Value	$ 0		(8,921,000)
Fair Value, Measurements, Recurring [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Cash Flow Hedge Asset at Fair Value	11,622,000
Interest Rate Cash Flow Hedge Liability at Fair Value	(580,000)		(20,539,000)
Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	(11,042,000)		(20,539,000)
Interest Rate Cash Flow Hedge Asset at Fair Value	11,622,000
Interest Rate Cash Flow Hedge Liability at Fair Value	(580,000)		$ (20,539,000)
Unsecured Debt [Member]
Derivatives, Fair Value [Line Items]
Unsecured Debt Repayment		$ 300,000,000
Unsecured Debt [Member] \| Unsecured Maturities [Member]
Derivatives, Fair Value [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0
Long-term Debt, Maturities, Repayments of Principal in Year Two	0
Long-term Debt, Maturities, Repayments of Principal in Year Three	$ 15,000,000