Shareholders' Equity - Components of Accumulated Other Comprehensive Income (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Components of Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 1,199,241
Current-period other comprehensive (loss) income	(1,339)
Ending balance	1,080,981
Foreign currency translation adjustments, net of tax attributable to The GEO Group, Inc.
Components of Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(7,470)
Current-period other comprehensive (loss) income	(5,858)
Ending balance	(13,328)
Change in fair value of derivatives, net of tax
Components of Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(11,892)
Current-period other comprehensive (loss) income	4,550
Ending balance	(7,342)
Pension adjustments, net of tax
Components of Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(5,084)
Current-period other comprehensive (loss) income	(31)
Ending balance	(5,115)
Total
Components of Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(24,446)
Ending balance	$ (25,785)