Mortgages Payable and Debt Maturities - Summary of Debt Obligation and Interest Rate Derivatives (Detail) $ in Thousands	Mar. 31, 2018 USD ($)
Debt Instrument [Line Items]
Payables due 2018	$ 279
Payables due 2019	130,393
Payables due 2020	100,413
Payables due 2021	103,122
Payables due 2022	394
Payables due Thereafter	1,432,980
Debt obligations	1,767,581
Line of credit - variable rate LIBOR + 1.10% (2.97% at March 31, 2018) [Member]
Debt Instrument [Line Items]
Payables due 2019	130,000
Debt obligations	130,000
Debt instrument, fair value	130,000
Term note - variable rate LIBOR + 1.15% (2.84% at March 31, 2018) [Member]
Debt Instrument [Line Items]
Payables due 2020	100,000
Debt obligations	100,000
Term note, fair value	100,000
Term Note - Fixed Rate 5.54% [Member]
Debt Instrument [Line Items]
Payables due 2021	100,000
Debt obligations	100,000
Term note, fair value	105,938
Term Note - Fixed Rate 4.533% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	175,000
Debt obligations	175,000
Term note, fair value	176,500
Term Note - Fixed Rate 3.50% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	600,000
Debt obligations	600,000
Term note, fair value	574,042
Term Note - Fixed Rate 3.875% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	450,000
Debt obligations	450,000
Term note, fair value	432,286
Term Note - Fixed Rate 3.67% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	200,000
Debt obligations	200,000
Term note, fair value	185,200
Mortgage Note - Fixed Rate 4.98% [Member]
Debt Instrument [Line Items]
Payables due 2018	39
Payables due 2019	56
Payables due 2020	59
Payables due 2021	2,748
Debt obligations	2,902
Debt instrument, fair value	2,947
Mortgage Note - Fixed Rate 4.065% [Member]
Debt Instrument [Line Items]
Payables due 2018	69
Payables due 2019	96
Payables due 2020	99
Payables due 2021	104
Payables due 2022	108
Payables due Thereafter	3,620
Debt obligations	4,096
Debt instrument, fair value	4,008
Mortgage Note - Fixed Rate 5.26% [Member]
Debt Instrument [Line Items]
Payables due 2018	50
Payables due 2019	71
Payables due 2020	74
Payables due 2021	78
Payables due 2022	83
Payables due Thereafter	3,566
Debt obligations	3,922
Debt instrument, fair value	4,053
Mortgage Note - Fixed Rate 5.99% [Member]
Debt Instrument [Line Items]
Payables due 2018	121
Payables due 2019	170
Payables due 2020	181
Payables due 2021	192
Payables due 2022	203
Payables due Thereafter	794
Debt obligations	1,661
Debt instrument, fair value	$ 1,746

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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