Significant Accounting Policies and Recently Issued Accounting Standards - Additional Information (Detail)		1 Months Ended	3 Months Ended				6 Months Ended		12 Months Ended
	Jan. 01, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2019 USD ($) Segment	Jun. 30, 2018 USD ($)	Dec. 31, 2017	Dec. 31, 2018 USD ($)	Jan. 01, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Expense on impairment of real estate assets			$ 0		$ 0		$ 0	$ 0
Insurance settlements receivable			9,000,000				9,000,000			$ 13,000,000
Income tax provision (benefits)			$ 1,000,000		$ 2,000,000		$ 6,000,000	$ 1,000,000
Corporate income tax rate							21.00%	21.00%	35.00%
REIT dividends qualified business income deduction			20.00%				20.00%
Federal deposit insurance corporation limit			$ 250,000				$ 250,000
Number of reportable business segment | Segment							1
Number of operating segments | Segment							1
Right of use assets			28,000,000				$ 28,000,000
Lease liabilities			28,000,000				28,000,000
Retained earnings				$ 1,000,000		$ (15,000,000)
ASC Topic 842 [Member]
Summary Of Significant Accounting Policies [Line Items]
Right of use assets	$ 27,000,000
Lease liabilities	27,000,000
Retained earnings	$ 1,000,000
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after ASC Topic 606 [Member]
Summary Of Significant Accounting Policies [Line Items]
Decrease in retained earnings											$ (15,000,000)
REIT [Member]
Summary Of Significant Accounting Policies [Line Items]
Income tax provision (benefits)		$ 0	$ 0				$ 0