Mortgages Payable and Debt Maturities - Summary of Debt Obligation and Interest Rate Derivatives (Detail) $ in Thousands	Sep. 30, 2019 USD ($)
Debt Instrument [Line Items]
Payables due 2019	$ 101
Payables due 2020	413
Payables due 2021	103,122
Payables due 2022	394
Payables due 2023	32,402
Payables due Thereafter	1,798,584
Debt obligations	1,935,016
Line of credit - variable rate LIBOR + 0.95% (3.00% at September 30, 2019) [Member]
Debt Instrument [Line Items]
Payables due 2023	25,000
Debt obligations	25,000
Debt instrument, fair value	25,000
Term Note - Fixed Rate 5.54% [Member]
Debt Instrument [Line Items]
Payables due 2021	100,000
Debt obligations	100,000
Term note, fair value	105,533
Term Note - Fixed Rate 4.533% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	175,000
Debt obligations	175,000
Term note, fair value	187,791
Term Note - Fixed Rate 3.50% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	600,000
Debt obligations	600,000
Term note, fair value	618,050
Term Note - Fixed Rate 3.875% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	450,000
Debt obligations	450,000
Term note, fair value	478,654
Term Note - Fixed Rate 3.67% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	200,000
Debt obligations	200,000
Term note, fair value	203,690
Term Note - Fixed Rate 4.00% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	350,000
Debt obligations	350,000
Term note, fair value	372,875
Mortgage Note - Fixed Rate 4.98% [Member]
Debt Instrument [Line Items]
Payables due 2019	14
Payables due 2020	59
Payables due 2021	2,748
Debt obligations	2,821
Debt instrument, fair value	2,879
Mortgage Note - Fixed Rate 4.065% [Member]
Debt Instrument [Line Items]
Payables due 2019	24
Payables due 2020	99
Payables due 2021	104
Payables due 2022	108
Payables due 2023	3,621
Debt obligations	3,956
Debt instrument, fair value	4,067
Mortgage Note - Fixed Rate 5.26% [Member]
Debt Instrument [Line Items]
Payables due 2019	19
Payables due 2020	74
Payables due 2021	78
Payables due 2022	83
Payables due 2023	3,565
Debt obligations	3,819
Debt instrument, fair value	4,118
Mortgage Note - Fixed Rate 4.4625% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	23,006
Debt obligations	23,006
Debt instrument, fair value	23,006
Mortgage Note - Fixed Rate 5.99% [Member]
Debt Instrument [Line Items]
Payables due 2019	44
Payables due 2020	181
Payables due 2021	192
Payables due 2022	203
Payables due 2023	216
Payables due Thereafter	578
Debt obligations	1,414
Debt instrument, fair value	$ 1,542

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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