Summary of Business Organization, Operations and Significant Accounting Policies - Comprehensive Income (Loss) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,199,241
Current-period other comprehensive income (loss)	828
Ending balance	1,040,503
Foreign currency translation adjustments, net of tax attributable to The GEO Group, Inc.
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(7,470)
Current-period other comprehensive income (loss)	(7,103)
Ending balance	(14,573)
Unrealized loss on derivatives, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(11,892)
Current-period other comprehensive income (loss)	6,146
Ending balance	(5,746)
Pension adjustments, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(5,084)
Current-period other comprehensive income (loss)	1,785
Ending balance	(3,299)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(24,446)
Ending balance	$ (23,618)