Segment information - Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Segment Reporting Information [Line Items]
Net sales	$ 875.1	$ 769.1	$ 1,727.1	$ 1,499.3
Adjusted EBITDA	204.9	179.0	388.8	332.0
Power Transmission
Segment Reporting Information [Line Items]
Net sales	549.6	510.8	1,095.6	996.4
Adjusted EBITDA	133.3	120.4	258.6	227.9
Fluid Power
Segment Reporting Information [Line Items]
Net sales	325.5	258.3	631.5	502.9
Adjusted EBITDA	$ 71.6	$ 58.6	$ 130.2	$ 104.1