Real Estate Transactions - Additional Information (Detail) $ in Thousands			3 Months Ended
	Jan. 24, 2018 Bed	Jan. 19, 2018 USD ($) ft²	Mar. 31, 2018 USD ($) Facility Bed	Mar. 31, 2017 USD ($)
Facility Activations Developments And Closures [Line Items]
Operating Expense			$ 319,151	$ 315,303
Idled Correctional Facilities
Facility Activations Developments And Closures [Line Items]
Number of facility | Facility			8
Idled Non-Core Facilities
Facility Activations Developments And Closures [Line Items]
Number of beds at the facility | Bed			440
Number of facility | Facility			2
Net Carrying Value			$ 4,000
Idle Facilities
Facility Activations Developments And Closures [Line Items]
Operating Expense			3,500	$ 2,600
Kansas Department Of Corrections
Facility Activations Developments And Closures [Line Items]
Lease term	20 years
Number of beds at the facility | Bed	2,432
Construction of new facility expected commencement description	Construction of the new facility commenced in the first quarter of 2018 with a timeline for completion of approximately 24 months
Construction of new facility approximate completion term	24 months
Construction project capitalized amount			1,400
Kansas Department Of Corrections | Private Placement
Facility Activations Developments And Closures [Line Items]
Loan costs			$ 600
Capital Commerce Center
Facility Activations Developments And Closures [Line Items]
Area of building acquired | ft²		261,000
Purchase price of real estate		$ 44,700
Percentage of building leased		98.00%
Purchase price, net tangible assets		$ 41,500
Purchase price, identifiable intangible assets		$ 3,200
Florida | Capital Commerce Center
Facility Activations Developments And Closures [Line Items]
Percentage of building leased		87.00%