Inventories (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
Dec. 31, 2015 |
|
| Inventory [Line Items] | |||||
| Inventories at FIFO, net of reserves | $ 622.8 | $ 622.8 | $ 524.6 | ||
| Less: LIFO reserve | (127.2) | (127.2) | (117.2) | ||
| Total inventories at LIFO, net of reserves | 495.6 | 495.6 | 407.4 | ||
| LIFO expense | 3.7 | $ 3.3 | 10.0 | $ 9.2 | |
| United States | |||||
| Inventory [Line Items] | |||||
| Less: LIFO reserve | $ (127.2) | $ (127.2) | $ (117.2) | ||