Income Taxes - Net Operating Losses and Income Tax Concessions (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Jan. 01, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income taxes
Net operating losses		$ 106.2	$ 42.2
Net operating loss carryforward		38.6	13.0
Valuation allowance		7.1	2.9
Period applicable for additional special income tax concession	5 years
Decrease (increase) in foreign income taxes due to special income tax concession in Singapore		$ 2.7	$ (7.7)	$ 6.3
Impact of income tax concession on basic earnings per common share (in dollars per share)		$ 0.04	$ (0.11)	$ 0.09
Impact of income tax concession on diluted earnings per common share (in dollars per share)		$ 0.04	$ (0.11)	$ 0.09
December 31, 2021
Income taxes
Net operating loss carryforward		$ 0.1
December 31, 2022
Income taxes
Net operating loss carryforward		0.1
December 31, 2023
Income taxes
Net operating loss carryforward		0.3
December 31, 2024
Income taxes
Net operating loss carryforward		0.6
December 31, 2025
Income taxes
Net operating loss carryforward		0.9
December 31, 2036
Income taxes
Net operating loss carryforward		31.8
Indefinite
Income taxes
Net operating loss carryforward		$ 4.8