Accumulated Other Comprehensive Loss - Schedule of Details of Comprehensive Loss (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 196.2
Other comprehensive (loss) income before reclassifications	(59.3)	$ 8.9
Less: amounts reclassified from accumulated other comprehensive loss	4.8	2.5	$ 1.9
Other comprehensive (loss) income	(54.5)	11.4	(62.1)
Balance at end of period	(172.5)	196.2
Intra-entity foreign currency translation adjustment	(721.7)	(728.6)
Unrecognized Pension Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	146.1	136.4
Other comprehensive (loss) income before reclassifications	(30.8)	(13.3)
Less: amounts reclassified from accumulated other comprehensive loss	4.4	3.6
Other comprehensive (loss) income	(26.4)	(9.7)
Balance at end of period	172.5	146.1	136.4
Cumulative Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	728.6	744.8
Other comprehensive (loss) income before reclassifications	6.9	16.2
Less: amounts reclassified from accumulated other comprehensive loss	0.0	0.0
Other comprehensive (loss) income	6.9	16.2
Balance at end of period	721.7	728.6	744.8
Cumulative Translation Adjustment | Intra-entity transactions
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Intra-entity foreign currency translation adjustment	37.0	(4.5)	65.8
Unrecognized Gain (Losses), on Derivative Instruments for Net Investment Hedge and Cash Flow Hedge | Net Investment Hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	34.5	41.9
Other comprehensive (loss) income before reclassifications	(33.0)	7.4
Less: amounts reclassified from accumulated other comprehensive loss	0.0	0.0
Other comprehensive (loss) income	(33.0)	7.4
Balance at end of period	67.5	34.5	41.9
Unrecognized Gain (Losses), on Derivative Instruments for Net Investment Hedge and Cash Flow Hedge | Cash Flow Hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(0.2)	(2.7)
Other comprehensive (loss) income before reclassifications	(2.4)	(1.4)
Less: amounts reclassified from accumulated other comprehensive loss	0.4	(1.1)
Other comprehensive (loss) income	(2.0)	(2.5)
Balance at end of period	1.8	(0.2)	(2.7)
Accumulated  Other Comprehensive  Loss, Net of  Taxes
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	909.0	920.4
Balance at end of period	$ 963.5	$ 909.0	$ 920.4