Summary of Business Organization, Operations and Significant Accounting Policies - Revenue Recognition (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) bed contract	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Disaggregation of Revenue [Line Items]
Domestic performance based revenues percent of consolidated revenues									1.00%
Performance obligation expected timing of satisfaction									P1Y
Performance obligation, payment required, period									30 days
Total Revenues	$ 599,430,000	$ 583,530,000	$ 583,509,000	$ 564,917,000	$ 568,977,000	$ 566,759,000	$ 577,070,000	$ 550,614,000	$ 2,331,386,000	$ 2,263,420,000	$ 2,179,490,000
Owned and Leased: Corrections & Detention
Disaggregation of Revenue [Line Items]
Total Revenues									1,110,749,000	1,055,254,000	1,042,613,000
Owned and Leased: Community-based
Disaggregation of Revenue [Line Items]
Total Revenues									170,805,000	149,619,000	72,953,000
Owned and Leased: Youth Services
Disaggregation of Revenue [Line Items]
Total Revenues									91,824,000	88,184,000	85,235,000
Managed Only
Disaggregation of Revenue [Line Items]
Total Revenues									641,079,000	582,091,000	490,027,000
Facility Construction and Design
Disaggregation of Revenue [Line Items]
Total Revenues									$ 4,226,000	115,404,000	252,401,000
Interest income, effective interest rate									8.97%
Non-residential Services and Other
Disaggregation of Revenue [Line Items]
Total Revenues									$ 312,703,000	272,868,000	236,261,000
U.S. Corrections & Detention
Disaggregation of Revenue [Line Items]
Total Revenues									1,492,973,000	1,438,044,000	1,375,277,000
U.S. Corrections & Detention | Owned and Leased: Corrections & Detention
Disaggregation of Revenue [Line Items]
Total Revenues									1,110,749,000	1,055,254,000	1,042,613,000
U.S. Corrections & Detention | Owned and Leased: Community-based
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
U.S. Corrections & Detention | Owned and Leased: Youth Services
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
U.S. Corrections & Detention | Managed Only
Disaggregation of Revenue [Line Items]
Total Revenues									382,224,000	382,790,000	332,664,000
U.S. Corrections & Detention | Facility Construction and Design
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
U.S. Corrections & Detention | Non-residential Services and Other
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
GEO Care
Disaggregation of Revenue [Line Items]
Total Revenues									580,313,000	514,166,000	394,449,000
GEO Care | Owned and Leased: Corrections & Detention
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
GEO Care | Owned and Leased: Community-based
Disaggregation of Revenue [Line Items]
Total Revenues									170,805,000	149,619,000	72,953,000
GEO Care | Owned and Leased: Youth Services
Disaggregation of Revenue [Line Items]
Total Revenues									91,824,000	88,184,000	85,235,000
GEO Care | Managed Only
Disaggregation of Revenue [Line Items]
Total Revenues									4,981,000	3,495,000	0
GEO Care | Facility Construction and Design
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
GEO Care | Non-residential Services and Other
Disaggregation of Revenue [Line Items]
Total Revenues									312,703,000	272,868,000	236,261,000
International
Disaggregation of Revenue [Line Items]
Total Revenues									253,874,000	195,806,000	157,363,000
International | Owned and Leased: Corrections & Detention
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
International | Owned and Leased: Community-based
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
International | Owned and Leased: Youth Services
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
International | Managed Only
Disaggregation of Revenue [Line Items]
Total Revenues									253,874,000	195,806,000	157,363,000
International | Facility Construction and Design
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
International | Non-residential Services and Other
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
Facility Construction and Design
Disaggregation of Revenue [Line Items]
Total Revenues									4,226,000	115,404,000	252,401,000
Facility Construction and Design | Owned and Leased: Corrections & Detention
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
Facility Construction and Design | Owned and Leased: Community-based
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
Facility Construction and Design | Owned and Leased: Youth Services
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
Facility Construction and Design | Managed Only
Disaggregation of Revenue [Line Items]
Total Revenues									0	0	0
Facility Construction and Design | Facility Construction and Design
Disaggregation of Revenue [Line Items]
Total Revenues									4,226,000	115,404,000	252,401,000
Facility Construction and Design | Non-residential Services and Other
Disaggregation of Revenue [Line Items]
Total Revenues									0	$ 0	$ 0
Department Of Justice, State Of Victoria | Facility Construction and Design
Disaggregation of Revenue [Line Items]
Total Revenues									$ 0
Number of contracts | contract									1
Number of beds in detention facility | bed									1,300
Facility operation contract term									25 years