Commitments and Contingencies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Bed LegalMatter CompensationPlan	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Aug. 27, 2015 Bed	Dec. 31, 1997 USD ($) Facility
Loss Contingencies [Line Items]
Number of pending legal proceedings that would have an effect on consolidated financial position, results of operations, or cash flows | LegalMatter	0
Number of beds at the facility | Bed	88,500			600
Total cash compensation under Deferred Compensation Plans	5.00%	5.00%	5.00%
Percentage of fixed return from Deferred Compensation Plans to participants	5.60%	5.60%	5.60%
Deferred Compensation Plans
Loss Contingencies [Line Items]
Employer discretionary matching contribution equal to employee contribution	100.00%	100.00%	100.00%
Number of qualified deferred compensation plans | CompensationPlan	2
Time period when distributions are paid, minimum years subsequent to the date an individual becomes a participant in the Plan	5 years
Distributions to senior executives commencement period, days after participant's separation from service	60 days
Distributions to senior executives commencement period following individual attains age sixty five	15 days
Deferred Compensation Plans assets	$ 16.9	$ 17.9
Matching contributions as general and administrative expense associated with the Deferred Compensation Plans	0.3	0.2	$ 0.2
Deferred Compensation Plans liability	$ 15.1	$ 15.7
Deferred Compensation Plans | After two years of service
Loss Contingencies [Line Items]
Vested percentage of employer contributions and investment earnings or losses	20.00%
Deferred Compensation Plans | After three years of service
Loss Contingencies [Line Items]
Vested percentage of employer contributions and investment earnings or losses	40.00%
Deferred Compensation Plans | After four years of service
Loss Contingencies [Line Items]
Vested percentage of employer contributions and investment earnings or losses	80.00%
Deferred Compensation Plans | After five or more years of service
Loss Contingencies [Line Items]
Vested percentage of employer contributions and investment earnings or losses	100.00%
Deferred Compensation Plans | Executive Officer
Loss Contingencies [Line Items]
Contribution as percentage of salary	50.00%
Contribution as percentage of cash bonus	100.00%
Deferred Compensation Plans | Non Employee Directors
Loss Contingencies [Line Items]
Contribution as percentage of retainer and meeting fees	100.00%
401(k) Savings and Retirement Plan (the "Plan")
Loss Contingencies [Line Items]
Minimum qualified service required to participate in the Savings and Retirement Plan, years	1 year
Eligible employee contribution on eligible compensation	90.00%
Employer discretionary matching contribution equal to employee contribution	100.00%	100.00%	100.00%
Maximum percentage of employer discretionary matching contribution of employee eligible compensation	5.00%	5.00%	5.00%
Minimum number of hours of employment in the plan year for discretionary matching contribution	One thousand
Discretionary contribution plan forfeitures, net	$ 12.0	$ 11.1	$ 11.8
401(k) Savings and Retirement Plan (the "Plan") | Minimum
Loss Contingencies [Line Items]
Age limit for participating in the Savings and Retirement Plan, years	18 years
401(k) Savings and Retirement Plan (the "Plan") | Prior to January 1, 2012 | After two years of service
Loss Contingencies [Line Items]
Vested percentage of employer contributions and investment earnings or losses	20.00%
401(k) Savings and Retirement Plan (the "Plan") | Prior to January 1, 2012 | After three years of service
Loss Contingencies [Line Items]
Vested percentage of employer contributions and investment earnings or losses	40.00%
401(k) Savings and Retirement Plan (the "Plan") | Prior to January 1, 2012 | After four years of service
Loss Contingencies [Line Items]
Vested percentage of employer contributions and investment earnings or losses	80.00%
401(k) Savings and Retirement Plan (the "Plan") | Prior to January 1, 2012 | After five or more years of service
Loss Contingencies [Line Items]
Vested percentage of employer contributions and investment earnings or losses	100.00%
Hardeman County Correctional Facilities Corporation
Loss Contingencies [Line Items]
Issuance of revenue bonds					$ 72.7
Number of beds at the facility | Facility					2,016
Outstanding principal balance of revenue bonds	$ 12.8
Outstanding principal balance of the bonds exceeded the purchase price option	$ 6.0