Indebtedness - Additional Information (Detail) - USD ($)												1 Months Ended							12 Months Ended
	Oct. 15, 2016	Oct. 05, 2016	Jun. 24, 2016	May 26, 2016	May 20, 2016	May 17, 2016	Mar. 15, 2016	Sep. 17, 2015	Apr. 13, 2015	Jan. 27, 2015	Oct. 25, 2013	Feb. 28, 2017	Oct. 31, 2016	May 31, 2016	Apr. 30, 2016	Mar. 31, 2016	Feb. 29, 2016	Jan. 31, 2016	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014	Dec. 21, 2016
Debt Instrument [Line Items]
Weighted Average Rate																			3.60%		3.70%
Outstanding Principal																			$ 750,188,000		$ 975,531,000
Cash paid for interest																			33,034,000		22,105,000		$ 9,170,000
Accrued interest payable outstanding																			491,000		1,239,000
Debt instrument repayment																			$ 390,089,000		$ 272,751,000		$ 26,001,000
Key Bank Senior Facility | Limited Partner | If greater than or equal to 50% of the revolver is used
Debt Instrument [Line Items]
Percentage of fee on line of credit facility outstanding								0.20%
Key Bank Senior Facility | Limited Partner | If less than 50% of the revolver is used
Debt Instrument [Line Items]
Percentage of fee on line of credit facility outstanding								0.25%
Key Bank Interim Facility
Debt Instrument [Line Items]
Repayments Of Lines Of Credit							$ 6,000,000							$ 30,000,000	$ 30,000,000		$ 23,784,000	$ 23,784,000
HNB Facility | 1-month LIBOR
Debt Instrument [Line Items]
Debt instrument interest rate											2.50%
Secured Credit Facility
Debt Instrument [Line Items]
Weighted Average Rate																			3.00%	[1],[2]	2.90%	[3]
Outstanding Principal																			$ 150,000,000	[1],[2]	$ 271,500,000	[3]
Secured credit facility borrowing capacity																			312,500,000		325,000,000
Credit facility outstanding	$ 10,000,000
Repayments Of Lines Of Credit		$ 47,335,000											$ 107,335,000
Secured Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Credit facility outstanding												$ 22,000,000
Secured Credit Facility | Key Bank Senior Facility
Debt Instrument [Line Items]
Secured credit facility borrowing capacity								$ 325,000,000
Deferred financing costs								4,722,000
Credit facility outstanding							$ 8,000,000									$ 45,476,000
Repayments Of Lines Of Credit														77,665,000
Secured credit facility, remaining borrowing capacity																			$ 162,500,000
Secured credit facility, unused fee percentage																			0.25%
Pledge of collateral security for credit facility																			85.00%
Secured Credit Facility | Key Bank Senior Facility | Limited Partner
Debt Instrument [Line Items]
Increase in maximum borrowing capacity								$ 450,000,000
Weighted Average Maturity (in years)								3 years
Secured credit facility, maturity date								Sep. 17, 2018
Secured Credit Facility | 1-month LIBOR | Key Bank Senior Facility
Debt Instrument [Line Items]
Debt instrument interest rate																			2.25%
Secured Credit Facility | 1-month LIBOR | Key Bank Senior Facility | Limited Partner | Minimum
Debt Instrument [Line Items]
Debt instrument interest rate								1.65%
Secured Credit Facility | 1-month LIBOR | Key Bank Senior Facility | Limited Partner | Maximum
Debt Instrument [Line Items]
Debt instrument interest rate								2.45%
Secured Credit Facility | Base Rate | Key Bank Senior Facility | Limited Partner | Minimum
Debt Instrument [Line Items]
Debt instrument interest rate								0.65%
Secured Credit Facility | Base Rate | Key Bank Senior Facility | Limited Partner | Maximum
Debt Instrument [Line Items]
Debt instrument interest rate								1.45%
Revolving credit agreement | Key Bank Senior Facility
Debt Instrument [Line Items]
Secured credit facility borrowing capacity								$ 125,000,000																$ 172,500,000
Percentage of secured credit facility available for swingline loans								10.00%
Percentage of secured credit facility available for issuance of letters of credit								10.00%
Term Loan | Key Bank Senior Facility
Debt Instrument [Line Items]
Secured credit facility borrowing capacity								$ 200,000,000
Senior Interim Term Loan | Key Bank Interim Facility
Debt Instrument [Line Items]
Secured credit facility borrowing capacity								120,000,000
Deferred financing costs								2,092,000
Senior Term Loan Facility
Debt Instrument [Line Items]
Repayment of term loan facility		$ 40,000,000
Senior Term Loan Facility | Key Bank Interim Facility
Debt Instrument [Line Items]
Secured credit facility borrowing capacity			$ 40,000,000
Secured credit facility, maturity date			Sep. 17, 2018
Credit facility outstanding			$ 40,000,000
Debt instrument closing costs			416,000
Debt instrument repayment			$ 33,512,000
Interest payment period																			Monthly
Principal date			Jun. 30, 2017
Periodic principal payment monthly			$ 100,000
Percentage of net proceeds from equity issuances, sales of assets, refinancing of assets			50.00%
Senior Term Loan Facility | 1-month LIBOR | Key Bank Interim Facility
Debt Instrument [Line Items]
Debt instrument interest rate			4.00%
Senior Term Loan Facility | Base Rate | Key Bank Interim Facility
Debt Instrument [Line Items]
Debt instrument interest rate			3.00%
Sponsor
Debt Instrument [Line Items]
Cash paid for interest																			$ 361,000		$ 965,000
Mortgages-Floating Rate
Debt Instrument [Line Items]
Weighted Average Rate																					2.80%
Outstanding Principal																			$ 0		$ 38,075,000
Mortgages-Fixed Rate
Debt Instrument [Line Items]
Weighted Average Rate																			3.80%		3.80%
Outstanding Principal																			$ 600,188,000		$ 545,956,000
Accrued interest payable outstanding																			$ 0
Debt instrument repayment																$ 43,694,000
Repayment of term loan facility																	$ 6,659,000
Mortgages-Fixed Rate | Aston
Debt Instrument [Line Items]
Outstanding Principal				$ 25,050,000
Weighted Average Maturity (in years)				30 years
Interest payment period																			Monthly
Principal date				Dec. 31, 2019
Debt interest rate				3.40%
Maturity date				Jun. 30, 2023
Mortgages-Fixed Rate | Craig Ranch
Debt Instrument [Line Items]
Outstanding Principal						$ 31,250,000
Weighted Average Maturity (in years)						30 years
Interest payment period																			Monthly
Principal date						May 31, 2019
Debt interest rate						3.30%
Maturity date						Jun. 30, 2023
Mortgages-Fixed Rate | Big Creek
Debt Instrument [Line Items]
Outstanding Principal					$ 49,680,000
Weighted Average Maturity (in years)					30 years
Interest payment period																			Monthly
Principal date					Jun. 30, 2019
Debt interest rate					3.70%
Maturity date					Jun. 30, 2026
Mortgages-Fixed Rate | Iron Rock Ranch
Debt Instrument [Line Items]
Outstanding Principal										$ 22,900,000
Interest payment period																			Monthly
Debt interest rate										3.40%
Maturity date										Feb. 01, 2025
Mortgages-Fixed Rate | Stonebridge At The Ranch
Debt Instrument [Line Items]
Outstanding Principal									$ 20,527,000
Interest payment period																			Monthly
Debt interest rate									3.20%
Maturity date									May 01, 2025
Mortgages-Fixed Rate | Creekstone At R T P
Debt Instrument [Line Items]
Outstanding Principal								$ 23,250,000
Weighted Average Maturity (in years)								30 years
Interest payment period																			Monthly
Principal date								Jun. 10, 2016
Debt interest rate								3.90%
Maturity date								Jun. 10, 2023
Mortgages-Fixed Rate | Fountains Southend
Debt Instrument [Line Items]
Outstanding Principal								$ 23,750,000
Weighted Average Maturity (in years)								30 years
Interest payment period																			Monthly
Principal date								Feb. 05, 2017
Debt interest rate								4.30%
Maturity date								Feb. 05, 2024
Mortgages-Fixed Rate | I R T Millenia
Debt Instrument [Line Items]
Outstanding Principal								$ 25,000,000
Weighted Average Maturity (in years)								30 years
Interest payment period																			Monthly
Principal date								Apr. 05, 2018
Debt interest rate								3.80%
Maturity date								Mar. 05, 2021
Mortgages-Fixed Rate | I R T Millenia | Supplemental Loan Agreement
Debt Instrument [Line Items]
Outstanding Principal								$ 4,175,000
Weighted Average Maturity (in years)								30 years
Interest payment period																			Monthly
Principal date								May 05, 2018
Debt interest rate								4.30%
Maturity date								Mar. 05, 2021
Mortgages-Fixed Rate | Talison Row
Debt Instrument [Line Items]
Outstanding Principal								$ 33,635,000
Weighted Average Maturity (in years)								30 years
Interest payment period																			Monthly
Principal date								Sep. 10, 2016
Debt interest rate								4.10%
Maturity date								Sep. 10, 2023
Mortgages-Fixed Rate | Aventine Greenville
Debt Instrument [Line Items]
Outstanding Principal								$ 30,600,000
Weighted Average Maturity (in years)								30 years
Interest payment period																			Monthly
Principal date								Nov. 04, 2016
Debt interest rate								3.20%
Maturity date								Mar. 05, 2021
Mortgages-Fixed Rate | Waterstone at Brier Creek
Debt Instrument [Line Items]
Outstanding Principal								$ 16,250,000
Interest payment period																			Monthly
Debt interest rate								3.70%
Maturity date								Apr. 05, 2022
Mortgages-Fixed Rate | Waterstone at Brier Creek | Supplemental Loan Agreement
Debt Instrument [Line Items]
Outstanding Principal								$ 4,175,000
Interest payment period																			Monthly
Debt interest rate								4.20%
Maturity date								Apr. 05, 2022
Mortgages-Fixed Rate | Key Bank Interim Facility
Debt Instrument [Line Items]
Repayments Of Lines Of Credit														$ 26,704,000
Mortgages-Fixed Rate | Key Bank Interim Facility | Minimum
Debt Instrument [Line Items]
Weighted Average Maturity (in years)														7 years
Mortgages-Fixed Rate | Key Bank Interim Facility | Maximum
Debt Instrument [Line Items]
Weighted Average Maturity (in years)														10 years

[1] As of December 31, 2016, IRT maintained a float-to-fixed interest rate swap with a $150,000 notional amount. This swap, which expires on June 17, 2021 and has a fixed rate of 1.145%, has converted $150,000 of our floating rate debt to fixed rate debt

[2] The secured credit facility total capacity is $312,500, of which $150,000 was outstanding as of December 31, 2016.

[3] The secured credit facility total capacity was $325,000, of which $271,500 was outstanding as of December 31, 2015