Earnings per Share Basic and Diluted EPS (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Numerator:
Net income	$ 23,904us-gaap_NetIncomeLoss	$ 40,004us-gaap_NetIncomeLoss
Denominators:
Weighted average Class A common shares outstanding - Basic	55,826	54,841
Weighted average Class B common shares outstanding	1,002	1,609
Dilutive effect of employee stock-based awards	293	455
Weighted average shares - Diluted	57,121	56,905
Earnings per common share attributable to Genesee & Wyoming Inc. common stockholders:
Basic earnings per common share	$ 0.43us-gaap_EarningsPerShareBasic	$ 0.73us-gaap_EarningsPerShareBasic
Diluted earnings per common share	$ 0.42us-gaap_EarningsPerShareDiluted	$ 0.70us-gaap_EarningsPerShareDiluted
Class A common shares [Member]
Denominators:
Weighted average Class A common shares outstanding - Basic	55,826	54,841

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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