Mortgages Payable and Debt Maturities - Summary of Debt Obligation and Interest Rate Derivatives (Detail) $ in Thousands	Jun. 30, 2019 USD ($)
Debt Instrument [Line Items]
Payables due 2019	$ 198
Payables due 2020	413
Payables due 2021	103,122
Payables due 2022	394
Payables due 2023	7,402
Payables due Thereafter	1,775,578
Debt obligations	1,887,107
Term Note - Fixed Rate 5.54% [Member]
Debt Instrument [Line Items]
Payables due 2021	100,000
Debt obligations	100,000
Term note, fair value	106,447
Term Note - Fixed Rate 4.533% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	175,000
Debt obligations	175,000
Term note, fair value	185,617
Term Note - Fixed Rate 3.50% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	600,000
Debt obligations	600,000
Term note, fair value	605,131
Term Note - Fixed Rate 3.875% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	450,000
Debt obligations	450,000
Term note, fair value	466,675
Term Note - Fixed Rate 3.67% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	200,000
Debt obligations	200,000
Term note, fair value	196,377
Term Note - Fixed Rate 4.00% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	350,000
Debt obligations	350,000
Term note, fair value	358,710
Mortgage Note - Fixed Rate 4.98% [Member]
Debt Instrument [Line Items]
Payables due 2019	28
Payables due 2020	59
Payables due 2021	2,748
Debt obligations	2,835
Debt instrument, fair value	2,899
Mortgage Note - Fixed Rate 4.065% [Member]
Debt Instrument [Line Items]
Payables due 2019	48
Payables due 2020	99
Payables due 2021	104
Payables due 2022	108
Payables due 2023	3,621
Debt obligations	3,980
Debt instrument, fair value	4,063
Mortgage Note - Fixed Rate 5.26% [Member]
Debt Instrument [Line Items]
Payables due 2019	36
Payables due 2020	74
Payables due 2021	78
Payables due 2022	83
Payables due 2023	3,565
Debt obligations	3,836
Debt instrument, fair value	4,103
Mortgage Note - Fixed Rate 5.99% [Member]
Debt Instrument [Line Items]
Payables due 2019	86
Payables due 2020	181
Payables due 2021	192
Payables due 2022	203
Payables due 2023	216
Payables due Thereafter	578
Debt obligations	1,456
Debt instrument, fair value	$ 1,575

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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Fair value portion of notes payable.

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