Earnings Per Common Share Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerators: [Abstract]
Net income attributable to Genesee & Wyoming Inc.	$ 55,562	$ 69,590	$ 44,168	$ 75,098	$ 426,566	$ 50,240	$ 46,007	$ 26,238	$ 244,418	$ 549,051	$ 141,137
Denominators: [Abstract]
Weighted average Class A common shares outstanding-Basic									59,745	61,579	57,324
Weighted average Class B common shares outstanding									644	735	790
Dilutive effect of employee stock-based awards									239	150	142
Weighted average shares—Diluted									60,628	62,464	58,256
Earnings per common share attributable to Genesee & Wyoming Inc. common stockholders:
Basic earnings per common share attributable to Genesee & Wyoming Inc. common stockholders: (US$ per share)	$ 0.96	$ 1.18	$ 0.74	$ 1.21	$ 6.90	$ 0.82	$ 0.75	$ 0.43	$ 4.09	$ 8.92	$ 2.46
Diluted earnings per common share attributable to Genesee & Wyoming Inc. common stockholders: (US$ per share)	$ 0.94	$ 1.16	$ 0.73	$ 1.19	$ 6.81	$ 0.80	$ 0.74	$ 0.42	$ 4.03	$ 8.79	$ 2.42