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, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerators: [Abstract]
Net income attributable to Genesee & Wyoming Inc.	$ 426,566	$ 50,240	$ 46,007	$ 26,238	$ 8,934	$ 56,785	$ 48,399	$ 27,019	$ 549,051	$ 141,137	$ 225,037
Denominators: [Abstract]
Weighted average Class A common shares outstanding-Basic									61,579	57,324	56,734
Weighted average Class B common shares outstanding									735	790	884
Dilutive effect of employee stock-based awards									150	142	230
Weighted average shares—Diluted									62,464	58,256	57,848
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)	$ 6.90	$ 0.82	$ 0.75	$ 0.43	$ 0.15	$ 0.99	$ 0.85	$ 0.47	$ 8.92	$ 2.46	$ 3.97
Diluted earnings per common share attributable to Genesee & Wyoming Inc. common stockholders: (US$ per share)	$ 6.81	$ 0.80	$ 0.74	$ 0.42	$ 0.15	$ 0.98	$ 0.83	$ 0.47	$ 8.79	$ 2.42	$ 3.89