Supplemental Cash Flow and Noncash Investing Transactions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Noncash or Part Noncash Divestitures [Line Items]
Noncash or Part Noncash Acquisition, Investments Acquired	$ 16,400,000
Noncash or Part Noncash Acquisition, Debt Assumed	$ 0	$ 0	$ 11,600,000
Number of railcars received	157		1,224
Supplemental Cash Flow Information
Interest Paid, Excluding Capitalized Interest, Operating Activities	$ 185,100,000	164,000,000.0	$ 154,600,000
Income taxes paid (refunded), net	11,600,000	18,100,000	21,500,000
Portfolio proceeds	$ 250,300,000	$ 234,400,000	$ 165,600,000