Selected Quarterly Financial Data (unaudited) (Narrative) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended |
---|---|---|
Dec. 31, 2017 |
Dec. 31, 2018 |
|
Environmental Exit Cost [Line Items] | ||
Reduction of tax provision | $ 464.0 | |
Bridgeton Closed Landfill | ||
Environmental Exit Cost [Line Items] | ||
Insurance recoveries | $ 40.0 |