Derivative Instruments and Fair Value Accounting Derivative Effect on Interest (Details) - Interest Expense [Member] - Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest Rate Swap, Expired, 2006 Secured Railcar Equipment Notes [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 0.0	$ (0.1)
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	0.1
Interest Rate Swap, Expired, 2018 Secured Railcar Equipment Notes [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.1	0.0
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	0.2
Interest Rate Swap, Expired, TRIP Holdings Warehouse Loan [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.5	0.7
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	2.1
Interest Rate Swap, Open, TRIP Master Funding Secured Railcar Equipment Notes [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.1	0.1
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	0.2
Interest Rate Cap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.0	0.0
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	0.1
Interest Rate Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.6	$ 0.0
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$ 2.4