Equity-Based Compensation - Summary of Target and Maximum Performance Goals (Details) - 2021 Multi Year Outperformance Plan	Jun. 03, 2021 shares
Below Threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Level (% of Absolute GNL LTIP Units Earned)	0.00%
Absolute TSR	24.00%
Number of Absolute GNL LTIP Units Earned (in shares)	0
Performance Level (% of Relative GNL LTIP Units Earned)	0.00%
Relative TSR Excess	(0.0600)
Number of Absolute GNL LTIP Units Earned (in shares)	0
Threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Level (% of Absolute GNL LTIP Units Earned)	25.00%
Absolute TSR	24.00%
Number of Absolute GNL LTIP Units Earned (in shares)	312,500
Performance Level (% of Relative GNL LTIP Units Earned)	25.00%
Relative TSR Excess	(0.0600)
Number of Absolute GNL LTIP Units Earned (in shares)	312,500
Target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Level (% of Absolute GNL LTIP Units Earned)	50.00%
Absolute TSR	30.00%
Number of Absolute GNL LTIP Units Earned (in shares)	625,000
Performance Level (% of Relative GNL LTIP Units Earned)	50.00%
Relative TSR Excess	0
Number of Absolute GNL LTIP Units Earned (in shares)	625,000
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Level (% of Absolute GNL LTIP Units Earned)	100.00%
Absolute TSR	36.00%
Number of Absolute GNL LTIP Units Earned (in shares)	1,250,000
Performance Level (% of Relative GNL LTIP Units Earned)	100.00%
Relative TSR Excess	0.0600
Number of Absolute GNL LTIP Units Earned (in shares)	1,250,000