Summary of Significant Accounting Policies - Non-cash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Other Significant Noncash Transactions [Line Items]
Accounts payable related to construction in progress	$ 16,700	$ 15,700
Receivable and reduction of real estate assets, net - related to hurricane	7,800	0
Dividends declared	78,690	76,700	$ 78,549
Conversion of Operating Partnership Units	900	0
Building [Member]
Other Significant Noncash Transactions [Line Items]
Assumption of building due to ground lease termination	$ 2,200	$ 0

Insurance receivable and reduction of real estate due to hurricane.

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Noncash or part noncash financial or equity instrument consideration redemption value.

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- Definition

Future cash outflow to pay for construction in progress expenditures that have occurred.

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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

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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.

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