Intangible Assets, Other Assets, Net and Goodwill Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Gross carrying amount	$ 639,636	$ 646,466
Accumulated amortization	(87,985)	(68,562)
Amortizable intangible assets, net	551,651	577,904
Weighted Average Amortization Period	40 years	40 years
Total intangible assets, net	587,663	613,933
Perpetual track access agreements
Non-amortizable intangible assets	35,891	35,891
Operating license
Non-amortizable intangible assets	121	138
Service agreements
Gross carrying amount	37,622	37,622
Accumulated amortization	(14,880)	(13,547)
Amortizable intangible assets, net	22,742	24,075
Weighted Average Amortization Period	28 years	28 years
Customer contracts and relationships
Gross carrying amount	177,179	178,603
Accumulated amortization	(26,738)	(22,899)
Amortizable intangible assets, net	150,441	155,704
Weighted Average Amortization Period	36 years	36 years
Track access agreements
Gross carrying amount	424,835	430,241
Accumulated amortization	(46,367)	(32,116)
Amortizable intangible assets, net	$ 378,468	$ 398,125
Weighted Average Amortization Period	43 years	43 years