Schedule III - Changes in Accumulated Depreciation (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Real estate held for sale		$ 146,615
Intangible lease assets	$ 403,138	443,134
Accumulated Depreciation	414,331	407,349	[1]	$ 292,786	$ 232,675
Accumulated amortization	$ 50,653	48,857
Real Estate Held For Sale [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Intangible lease assets		15,800
Accumulated Depreciation		500
Accumulated amortization		100
Real Estate Held For Sale [Member] | Land and Building [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Real estate held for sale		$ 131,400

[1] Includes $0.5 million of accumulated depreciation reflected in real estate held for sale at December 31, 2017. Excludes accumulated amortization related to intangible lease assets that are included in real estate held for sale of $0.1 million at December 31, 2017.