XML 56 R37.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Derivative Financial Instruments - Additional Information (Detail) - USD ($) | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 31, 2017 | Mar. 31, 2018 | Dec. 31, 2016 | Jun. 24, 2016
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Derivative, notional amount | $ 350,000,000 |  | $ 350,000,000 |
Realized (gains) losses on interest rate hedges reclassified to earnings | 132,000 |  |  |
Interest Rate Swap |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Derivative, notional amount | $ 150,000,000 |  |  |
Derivative, maturity date | Jun. 17, 2021 |  |  |
Cash Flow Hedge |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Derivative, strike rate for the interest rate swap contract |  |  |  | 1.145%
Cash Flow Hedge | Interest Rate Swap |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Derivative, notional amount | $ 150,000,000 |  | $ 150,000,000 | $ 150,000,000
Derivative, maturity date | Jun. 17, 2021 |  |  |
Cash Flow Hedge | Interest Rate Swaps and Caps | Scenario, Forecast |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Reclassified out of accumulated other comprehensive income to earnings, amount |  | $ 111,000 |  |

X
- 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

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

X
- Definition The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as 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 4C -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4D -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624177-113959 + Details
Name: | us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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

X
- Definition Fixed interest rate that will be received or paid upon exercise of the interest rate swaption contract. + References No definition available. + Details
Name: | us-gaap_DerivativeSwaptionInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959 + Details
Name: | us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=irt_InterestRateSwapsAndCapsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |