Intangible Assets, Other Assets, Net and Goodwill (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011 years	Dec. 31, 2010 years
Gross Carrying Amount	$ 230,131	$ 230,213
Accumulated Amortization	35,525	28,883
Net Assets	194,606	201,330
Weighted Average Amortization Period	37	37
Total intangible assets	230,628	237,355
Perpetual track access agreements
Indefinite-lived Intangible Assets	35,891	35,891
Operating license
Indefinite-lived Intangible Assets	131	134
Service agreements
Gross Carrying Amount	37,622	37,622
Accumulated Amortization	10,881	9,548
Net Assets	26,741	28,074
Weighted Average Amortization Period	28	28
Customer contracts and relationships
Gross Carrying Amount	57,859	58,741
Accumulated Amortization	14,501	12,334
Net Assets	43,358	46,407
Weighted Average Amortization Period	27	27
Track access agreements
Gross Carrying Amount	134,650	133,850
Accumulated Amortization	10,143	7,001
Net Assets	$ 124,507	$ 126,849
Weighted Average Amortization Period	43	43