- Earnings Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share, Basic and Diluted [Abstract]
Net income	$ 39,229	$ 38,453	$ 111,474	$ 109,761
Net loss attributable to noncontrolling interests	60	36	223	123
Net income attributable to The GEO Group, Inc.	$ 39,289	$ 38,489	$ 111,697	$ 109,884
Basic earnings per share attributable to The GEO Group, Inc.:
Weighted average shares outstanding (in shares)	119,681	122,251	120,567	119,356
Per share amount (USD per share)	$ 0.33	$ 0.31	$ 0.93	$ 0.92
Diluted earnings per share attributable to The GEO Group, Inc.:
Weighted average shares outstanding (in shares)	119,681	122,251	120,567	119,356
Dilutive effect of equity incentive plans (in shares)	621	636	488	758
Weighted average shares assuming dilution (in shares)	120,302	122,887	121,055	120,114
Income from continuing operations (USD per share)	$ 0.33	$ 0.31	$ 0.92	$ 0.91