Schedule III - Real Estate and Accumulated Depreciation Summary of Transactions (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Investment in Real Estate, balance at beginning of period	$ 3,078,902		$ 3,049,672	$ 2,972,528
Additions through capital expenditures	45,929		30,376	77,233
Sale of real estate for cash	(4,368)		(554)	(81)
Asset impairments	(49,247)
Reclassifications and other	(122)		(592)	(8)
Investment in Real Estate, balance at end of period	3,071,094		3,078,902	3,049,672
Accumulated Depreciation, balance at beginning of period	(755,761)		(680,965)	(607,771)
Depreciation	(79,745)		(75,069)	(73,260)
Disposals	118		273	66
Asset impairments	19,408
Accumulated Depreciation, balance at end of period	$ (815,980)	[1]	$ (755,761)	$ (680,965)

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