Asset Impairments and Assets Held for Sale Asset Held For Sale (Details)	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) Vessel
Long Lived Assets Held-for-sale [Line Items]
Asset Impairment Charges	$ 8,600,000	$ 38,500,000	$ 33,900,000
Assets Held-for-sale, Long Lived, Fair Value Disclosure	4,500,000	89,500,000
Portfolio Management [Member]
Long Lived Assets Held-for-sale [Line Items]
Gain (Loss) on Disposition of Assets	1,800,000	5,200,000	21,600,000
Asset Impairment Charges	3,700,000	6,700,000	31,000,000
Assets Held-for-sale, Long Lived, Fair Value Disclosure	0	45,600,000
Rail North America [Member]
Long Lived Assets Held-for-sale [Line Items]
Asset Impairment Charges	4,600,000	31,200,000	$ 2,500,000
Assets Held-for-sale, Long Lived, Fair Value Disclosure	4,500,000	43,900,000
Nordic Vessels [Member]
Long Lived Assets Held-for-sale [Line Items]
Number Of Vessels | Vessel			6
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Long Lived Assets Held-for-sale [Line Items]
Railcars in Flammable Service		2,400
Adler Funding Llc [Member]
Long Lived Assets Held-for-sale [Line Items]
Asset Impairment Charges	3,000,000
Cardinal Marine [Member]
Long Lived Assets Held-for-sale [Line Items]
Asset Impairment Charges	$ 0	$ 0	$ 19,000,000
Railcars [Member]
Long Lived Assets Held-for-sale [Line Items]
Assets		90