Summary of Business Organization, Operations and Significant Accounting Policies - Comprehensive Income (Loss) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 975,056
Current-period other comprehensive income (loss)	6,379
Ending balance	1,199,241
Foreign currency translation adjustments, net of tax attributable to The GEO Group, Inc.
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(11,284)
Current-period other comprehensive income (loss)	3,814
Ending balance	(7,470)
Unrealized loss on derivatives, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(15,877)
Current-period other comprehensive income (loss)	3,985
Ending balance	(11,892)
Pension adjustments, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,664)
Current-period other comprehensive income (loss)	(1,420)
Ending balance	(5,084)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(30,825)
Ending balance	$ (24,446)