Intangible Assets and Goodwill Intangible Assets (Details) £ in Thousands, AUD in Thousands, $ in Thousands					12 Months Ended
	May 03, 2017 GBP (£)	May 03, 2017 USD ($)	Dec. 01, 2016 AUD	Dec. 01, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Gross Carrying Amount					$ 1,774,277	$ 1,580,784
Accumulated Amortization					(207,359)	(144,405)
Intangible Assets, Net					$ 1,566,918	$ 1,436,379
Weighted Average Amortization Period (in Years)					46 years	48 years
Total intangible assets, net					$ 1,567,038	$ 1,472,376
Perpetual track access agreements
Non-amortizable intangible assets						35,891
Operating license
Non-amortizable intangible assets					120	106
Operational Network Rights [Member]
Gross Carrying Amount					495,088	399,751
Accumulated Amortization					(13,260)	(7,050)
Intangible Assets, Net					$ 481,828	$ 392,701
Weighted Average Amortization Period (in Years)					92 years	100 years
Track access agreements [Member]
Gross Carrying Amount					$ 467,098	$ 416,878
Accumulated Amortization					(91,059)	(72,442)
Intangible Assets, Net					$ 376,039	$ 344,436
Weighted Average Amortization Period (in Years)					41 years	43 years
Customer contracts and relationships [Member]
Gross Carrying Amount					$ 796,354	$ 750,057
Accumulated Amortization					(100,621)	(63,520)
Intangible Assets, Net					$ 695,733	$ 686,537
Weighted Average Amortization Period (in Years)					24 years	24 years
Trade names/trademarks [Member]
Gross Carrying Amount					$ 13,296	$ 11,888
Accumulated Amortization					(919)	(524)
Intangible Assets, Net					$ 12,377	$ 11,364
Weighted Average Amortization Period (in Years)					40 years	40 years
Favorable operating leases [Member]
Gross Carrying Amount					$ 2,441	$ 2,210
Accumulated Amortization					(1,500)	(869)
Intangible Assets, Net					$ 941	$ 1,341
Weighted Average Amortization Period (in Years)					5 years	5 years
Pentalver Transport Limited [Member]
Weighted Average Amortization Period (in Years)	33 years	33 years
Pentalver Transport Limited [Member] | Operational Network Rights [Member]
Fair values assigned to amortizable intangible assets	£ 42,000	$ 54,239
GRail [Member] | Customer Contracts [Member]
Fair values assigned to amortizable intangible assets			AUD 635,000	$ 470,599
U.K./European Operations [Member] | ERS Railways [Member] | Customer contracts and relationships [Member]
Impairment of Intangible Assets, Finite-lived						$ 4,100