v3.3.1.900
Other long-term liabilities (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Other long-term liabilities    
Asset retirement obligations $ 48.5 $ 51.2
Net pension liability 0.6 3.1
Deferred revenue 0.5 0.9
Accrued LTIP and director share units 1.1 1.1
Other 2.5 3.3
Other Liabilities, Noncurrent, Total 53.2 59.6
Asset retirement obligations rollforward    
Asset retirement obligations beginning of year 51.2 54.0
Accretion of asset retirement obligations 1.1 1.3
Translation adjustments (3.8) (2.1)
Sale of Greeley   (2.0)
Asset retirement obligations, end of year $ 48.5 $ 51.2