Concentrations	12 Months Ended
Dec. 31, 2018
Risks and Uncertainties [Abstract]
Concentrations	Concentration of Revenues We derived revenue from a wide range of industries and companies. In 2018, we generated approximately 25% of our total revenues from customers in the petroleum industry, 18% from the chemical industry, 17% from the transportation industry, 9% from the mining, minerals and aggregates industry, and 9% from food/agriculture industries. Our foreign identifiable revenues were primarily derived in Canada, Germany, Poland, Mexico, and Austria. Concentration of Credit Risk We did not have revenue concentrations greater than 10% from any particular customer for any of the years ended December 31, 2018, 2017, and 2016. Under our lease agreements with customers, we typically retain legal ownership of the assets unless such assets have been financed by sale-leasebacks. We perform a credit evaluation prior to approval of a lease contract. Subsequently, we monitor the creditworthiness of the customer and the value of the collateral on an ongoing basis. We maintain an allowance for losses to provide for credit losses inherent in our receivables balances. Concentration of Labor Force As of December 31, 2018, collective bargaining agreements covered approximately 42% of our employees, of which agreements covering 26% of employees will expire within the next year. The hourly employees at our US service centers are represented by the United Steelworkers. Employees at three of Rail North America's Canadian service centers are represented by Unifor, the union formerly known as the Communication, Energy and Paperworkers Union of Canada, and the Employee Shop Committee of Riviere-des-Prairies. The unlicensed shipboard personnel on nine of the ASC vessels are represented by the Seafarers International Union. Licensed personnel on ASC’s vessels, other than captains, are represented by the American Maritime Officers. Certain employees of GATX Rail Europe are represented by one union in Germany and three unions in Poland. We have begun negotiating new terms for the agreements expiring in 2019, and no work interruptions or other adverse events are currently expected.

Concentration of Revenues

We derived revenue from a wide range of industries and companies. In 2018, we generated approximately 25% of our total revenues from customers in the petroleum industry, 18% from the chemical industry, 17% from the transportation industry, 9% from the mining, minerals and aggregates industry, and 9% from food/agriculture industries. Our foreign identifiable revenues were primarily derived in Canada, Germany, Poland, Mexico, and Austria.

Concentration of Credit Risk

We did not have revenue concentrations greater than 10% from any particular customer for any of the years ended December 31, 2018, 2017, and 2016. Under our lease agreements with customers, we typically retain legal ownership of the assets unless such assets have been financed by sale-leasebacks. We perform a credit evaluation prior to approval of a lease contract. Subsequently, we monitor the creditworthiness of the customer and the value of the collateral on an ongoing basis. We maintain an allowance for losses to provide for credit losses inherent in our receivables balances.

Concentration of Labor Force

As of December 31, 2018, collective bargaining agreements covered approximately 42% of our employees, of which agreements covering 26% of employees will expire within the next year. The hourly employees at our US service centers are represented by the United Steelworkers. Employees at three of Rail North America's Canadian service centers are represented by Unifor, the union formerly known as the Communication, Energy and Paperworkers Union of Canada, and the Employee Shop Committee of Riviere-des-Prairies. The unlicensed shipboard personnel on nine of the ASC vessels are represented by the Seafarers International Union. Licensed personnel on ASC’s vessels, other than captains, are represented by the American Maritime Officers. Certain employees of GATX Rail Europe are represented by one union in Germany and three unions in Poland. We have begun negotiating new terms for the agreements expiring in 2019, and no work interruptions or other adverse events are currently expected.