Schedule III - Real Estate Assets and Accumulated Depreciation (Parenthetical) (Detail) $ in Billions	12 Months Ended
	Dec. 31, 2018 USD ($)
SEC Schedule III, Real Estate Assets and Accumulated Depreciation [Line Items]
Aggregate cost of properties for federal Income Tax purposes	$ 3.9
Maximum
SEC Schedule III, Real Estate Assets and Accumulated Depreciation [Line Items]
Prison facilities, estimated useful lives of depreciable assets	50 years