Property and Equipment and Leases Leases (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leased Assets [Line Items]
Leased railcars	18,583	17,718
Leased locomotives	162	100
Revenues from leased railroads as a percentage of total operating revenues	9.00%
Revenues from leased railroads subject to expiration in each of the next 10 years as a percentage of annual total operating revenues	3.00%
Equipment [Member]
Operating Leased Assets [Line Items]
Operating lease expense	$ 29,462	$ 32,050	$ 13,386
Real property [Member]
Operating Leased Assets [Line Items]
Operating lease expense	8,361	8,062	5,055
Trackage rights [Member]
Operating Leased Assets [Line Items]
Operating lease expense	$ 53,783	$ 50,911	$ 28,250