Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands													12 Months Ended
	Jan. 11, 2019	Oct. 12, 2018	Jul. 13, 2018	Apr. 13, 2018	Jan. 12, 2018	Oct. 13, 2017	Jul. 14, 2017	Apr. 14, 2017	Jan. 13, 2017	Oct. 14, 2016	Jul. 08, 2016	Apr. 08, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Significant Accounting Policies [Line Items]
Ownership percent of VIE													93.80%
Capitalized transaction costs													$ 5,800
Intangibles including goodwill													12,100	$ 12,100
Intangible assets													4,300	4,300
Goodwill													7,800	7,800
Accumulated amortization of identified intangible assets													3,000	2,900
Amortization of in-place leases													7,187	2,231	$ 3,373
Cash and cash equivalents, restricted cash													21,100	17,200
Liabilities related to assets held for sale													11,200
Deferred financing costs													26,400	23,700
Long-term debt													2,374,700	2,193,700
Accumulated amortization for deferred financing costs													36,600	33,900
Operating loss carryforwards													74,100	74,100
Operating loss carryforward, offset against tax and distribution requirements														$ 14,000
Net investment in real estate U.S federal tax basis													3,400,000
Net investment in notes receivable U.S federal tax basis													$ 37,100
Tax status of Common Shares distributions deemed paid during the year:
Ordinary income (usd per share)													$ 2.137	$ 1.657	$ 1.471
Long-term capital gains (usd per share)													0.000	0.718	0.000
Nondividend distributions (usd per share)													0.000	0.000	0.179
Distributions declared per Common Share outstanding (usd per share)													2.137	$ 2.375	$ 1.650
Quarterly distribution paid per common share (usd per share)		$ 0.55	$ 0.55	$ 0.55	$ 0.4875	$ 0.4875	$ 0.4875	$ 0.4875	$ 0.4250	$ 0.4250	$ 0.4250	$ 0.4250	$ 0.487
Proceeds from insurance claims													$ 7,943	$ 3,626	$ 1,145
Distributions of capital from unconsolidated joint ventures													396	789	3,068
Fair Value, Inputs, Level 2
Significant Accounting Policies [Line Items]
Mortgage notes payable, fair value													2,364,600	2,184,000
Identified Intangible Assets
Significant Accounting Policies [Line Items]
Amortization of in-place leases													$ 100	$ 100	200
Subsequent Event
Tax status of Common Shares distributions deemed paid during the year:
Quarterly distribution paid per common share (usd per share)	$ 0.55
Quarterly distribution for tax purposes	$ 0.063000
Accounting Standards Update 2016-15
Tax status of Common Shares distributions deemed paid during the year:
Proceeds from distributions															$ (1,000)