Supplemental Cash Flow and Noncash Investing Transactions (Details Textual) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) Car	Dec. 31, 2014 USD ($) Car
Noncash or Part Noncash Divestitures [Line Items]
Portfolio proceeds	$ 223.7	$ 482.2	$ 264.0
Supplemental Cash Flow and Noncash Investing and Financing Transactions (Textual) [Abstract]
Aggregate fair value of liquidating distributions			$ 1.1
Number of railcars received \| Car		157	62

The fair value of assets acquired in noncash investing or financing activities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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Balance Type:	debit
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