Schedule III - Real Estate Assets and Accumulated Depreciation Summary of Transactions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018
SEC Schedule III, Real Estate Assets and Accumulated Depreciation [Line Items]
Investment in Real Estate, balance at beginning of period	$ 3,605,137		$ 3,697,160	$ 3,367,358
Additions through capital expenditures	29,142		64,423	26,547
Acquisitions	82,324		8,809	269,271
Asset impairments	(10,154)		(4,040)
Reclassifications and other	(111,171)		(161,215)	33,984
Investment in Real Estate, balance at end of period	3,595,278	[1]	3,605,137	3,697,160
Accumulated Depreciation, balance at beginning of period	(1,053,670)		(1,075,389)	(976,121)
Depreciation	(89,008)		(87,492)	(99,361)
Disposals/Other	14,115		109,211	93
Accumulated Depreciation, balance at end of period	$ (1,128,563)	[2]	$ (1,053,670)	$ (1,075,389)

[1] The aggregate cost of properties for federal income tax purposes is approximately $4.0 billion at December 31, 2020.

[2] Depreciation is calculated using estimated useful lives of depreciable assets up to 50 years for prison facilities.