Schedule III - Real Estate Assets and Accumulated Depreciation Summary of Transactions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2017
SEC Schedule III, Real Estate Assets and Accumulated Depreciation [Line Items]
Investment in Real Estate, balance at beginning of period	$ 3,697,160		$ 3,367,358	$ 3,306,896
Additions through capital expenditures	64,423		26,547	29,730
Acquisitions	8,809		269,271	37,827
Asset impairments	(4,040)			(879)
Reclassifications and other	(161,215)		33,984	(6,216)
Investment in Real Estate, balance at end of period	3,605,137	[1]	3,697,160	3,367,358
Accumulated Depreciation, balance at beginning of period	(1,075,389)		(976,121)	(888,745)
Depreciation	(87,492)		(99,361)	(94,116)
Disposals/Other	109,211		93	6,162
Asset impairments				578
Accumulated Depreciation, balance at end of period	$ (1,053,670)	[2]	$ (1,075,389)	$ (976,121)

[1] The aggregate cost of properties for federal income tax purposes is approximately $4.0 billion at December 31, 2019.

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