Segment information - Information About Unconsolidated Equity Affiliates (Details) - USD ($) $ in Millions |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract] | |||
Carrying value of investments at year end | $ 4.0 | $ 3.5 | |
Share in earnings (losses) of equity affiliates | 0.4 | (1.5) | $ 0.5 |
Asian countries | Global Markets | |||
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract] | |||
Carrying value of investments at year end | 4.0 | 3.5 | 4.9 |
Undistributed earnings | 2.6 | 2.5 | 2.2 |
Share in earnings (losses) of equity affiliates | $ 0.4 | $ (1.5) | $ 0.5 |