Fair value of financial instruments (Details) $ in Millions		3 Months Ended			6 Months Ended
	Jul. 15, 2022 USD ($)	Jun. 30, 2023 USD ($) derivative_instrument	Dec. 31, 2022 USD ($) Instruments derivative_instrument	Jun. 30, 2022 USD ($) derivative_instrument	Jun. 30, 2023 USD ($) derivative_instrument	Jun. 30, 2022 USD ($) derivative_instrument	Jul. 26, 2023 USD ($)	Oct. 03, 2022 USD ($)	Jul. 21, 2022 USD ($)	Jul. 12, 2022 USD ($) derivative_instrument	Sep. 30, 2021 derivative_instrument	Dec. 31, 2019 derivative_instrument
Debt Securities, Available-for-sale [Line Items]
Other operating income (expense)		$ (3.8)		$ 2.4	$ 4.5	$ 2.7
Foreign currency transaction gains					(18.2)	(13.4)
Interest expense		51.1		32.4	97.7	60.3
Contingent consideration payment					9.7	2.5
G4S
Debt Securities, Available-for-sale [Line Items]
Contingent consideration		22.0			22.0
NoteMachine
Debt Securities, Available-for-sale [Line Items]
Contingent consideration								$ 14.8
NoteMachine | ATM Cash Withdrawal Interchange Fees
Debt Securities, Available-for-sale [Line Items]
Contingent consideration								4.3
Contingent consideration derecognition gain		4.8			4.8
NoteMachine | Post-Acquisition Collection of ATM Tax Rate Rebates
Debt Securities, Available-for-sale [Line Items]
Contingent consideration								$ 10.5
Contingent consideration payment					9.0
Not Designated as Hedging Instrument | Foreign Exchange Contract
Debt Securities, Available-for-sale [Line Items]
Notional value of nonderivative instruments					$ 554.0
Weighted average maturity					1 month
Not Designated as Hedging Instrument | Foreign Exchange Contract | Other operating income (expense)
Debt Securities, Available-for-sale [Line Items]
Gain (loss) on foreign currency contract		10.4		14.1	$ 18.6	33.0
Not Designated as Hedging Instrument | Foreign Exchange Contract | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of derivative instruments, net		2.2	$ (7.0)		2.2
Designated as Hedging Instrument | Level 2
Debt Securities, Available-for-sale [Line Items]
Net derivative instrument (gains) losses included in interest expense		(6.5)		0.2	$ (11.9)	1.1
Designated as Hedging Instrument | Currency Swap
Debt Securities, Available-for-sale [Line Items]
Weighted average maturity					3 months 18 days
Notional value of derivative instrument		41.0			$ 41.0
Other operating income (expense)		3.8		(5.3)	7.2	6.5
Foreign currency transaction gains		3.8		(5.3)	7.2	6.5
Interest expense		0.2		0.3	0.5	0.7
Foreign currency derivative instrument gains (losses)		(4.0)		5.0	(7.7)	(7.2)
Designated as Hedging Instrument | Currency Swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of contract, asset position		8.1	14.6		$ 8.1
Designated as Hedging Instrument | $400 million interest rate swap
Debt Securities, Available-for-sale [Line Items]
Weighted average maturity					3 months 18 days
Notional value of derivative instrument		400.0			$ 400.0
Number of instruments held | derivative_instrument												10
Designated as Hedging Instrument | $400 million interest rate swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		6.8	10.0		6.8
Net derivative instrument (gains) losses included in interest expense		(5.0)		$ 1.8	$ (9.0)	$ 4.2
Designated as Hedging Instrument | $200 million interest rate swap
Debt Securities, Available-for-sale [Line Items]
Number of instruments held | derivative_instrument				4		4
Designated as Hedging Instrument | $200 million interest rate swap | Gains (losses) on cash flow hedges
Debt Securities, Available-for-sale [Line Items]
Cumulative net gain in AOCI			$ 9.2
Designated as Hedging Instrument | $200 million interest rate swap amended
Debt Securities, Available-for-sale [Line Items]
Weighted average maturity					2 years
Notional value of derivative instrument		200.0			$ 200.0
Number of instruments held | derivative_instrument			3
Designated as Hedging Instrument | $200 million interest rate swap amended | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		16.8	$ 16.4		$ 16.8				$ 9.2
Designated as Hedging Instrument | $175 million interest rate swap
Debt Securities, Available-for-sale [Line Items]
Weighted average maturity					2 years
Notional value of derivative instrument		175.0			$ 175.0
Number of instruments held | Instruments			2
Designated as Hedging Instrument | $175 million interest rate swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		2.9			$ 2.9
Fair value of swap, net			$ 1.0
Designated as Hedging Instrument | $400 million interest rate swap 2023
Debt Securities, Available-for-sale [Line Items]
Weighted average maturity					2 years 3 months 18 days
Notional value of derivative instrument		$ 400.0			$ 400.0
Number of instruments held | derivative_instrument		8			8
Designated as Hedging Instrument | $400 million interest rate swap 2023 | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		$ 8.6			$ 8.6
Designated as Hedging Instrument | $400 million cross currency swap
Debt Securities, Available-for-sale [Line Items]
Number of instruments held | derivative_instrument											10
Cash proceeds from settlement of cross currency swap	$ 67.0
Designated as Hedging Instrument | $400 million cross currency swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Net derivative instrument (gains) losses included in interest expense				$ (1.6)		$ (3.1)
Designated as Hedging Instrument | $400 million cross currency swap 2022
Debt Securities, Available-for-sale [Line Items]
Notional value of derivative instrument		400.0			400.0					$ 400.0
Number of instruments held | derivative_instrument										9
Designated as Hedging Instrument | $400 million cross currency swap 2022 | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of contract, liability position		23.3	11.7		23.3
Net derivative instrument (gains) losses included in interest expense		(1.5)			$ (2.9)
Designated as Hedging Instrument | $215 million cross currency swap
Debt Securities, Available-for-sale [Line Items]
Weighted average maturity					2 years 4 months 24 days
Notional value of derivative instrument										$ 215.0
Designated as Hedging Instrument | $185 million cross currency swap
Debt Securities, Available-for-sale [Line Items]
Weighted average maturity					6 years 6 months
Notional value of derivative instrument										$ 185.0
Designated as Hedging Instrument | $215 million cross currency swap II | Subsequent Event
Debt Securities, Available-for-sale [Line Items]
Notional value of derivative instrument							$ 215.0
Prepaid expenses and other | Not Designated as Hedging Instrument | Foreign Exchange Contract | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of derivative instruments, asset		3.7	3.5		$ 3.7
Prepaid expenses and other | Designated as Hedging Instrument | $400 million interest rate swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position			9.3
Prepaid expenses and other | Designated as Hedging Instrument | $200 million interest rate swap amended | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		6.8	6.0		6.8
Prepaid expenses and other | Designated as Hedging Instrument | $175 million interest rate swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		2.8	2.0		2.8
Prepaid expenses and other | Designated as Hedging Instrument | $400 million interest rate swap 2023 | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		3.2			3.2
Prepaid expenses and other | Designated as Hedging Instrument | $400 million cross currency swap 2022 | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of contract, liability position		5.6	5.6		5.6
Other assets | Designated as Hedging Instrument | $400 million interest rate swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position			0.7
Other assets | Designated as Hedging Instrument | $200 million interest rate swap amended | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		10.0	10.4		10.0
Other assets | Designated as Hedging Instrument | $175 million interest rate swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		0.1			0.1
Other assets | Designated as Hedging Instrument | $400 million interest rate swap 2023 | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, asset position		5.4			5.4
Accrued liabilities | Not Designated as Hedging Instrument | Foreign Exchange Contract | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of derivative instruments, liability		1.5	10.5		1.5
Other liabilities | Designated as Hedging Instrument | $175 million interest rate swap | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of swap, liability position			1.0
Other liabilities | Designated as Hedging Instrument | $400 million cross currency swap 2022 | Level 2
Debt Securities, Available-for-sale [Line Items]
Fair value of contract, liability position		28.9	17.3		28.9
Six hundred million senior unsecured notes
Debt Securities, Available-for-sale [Line Items]
Carrying value		600.0	600.0		600.0
Six hundred million senior unsecured notes | Level 3
Debt Securities, Available-for-sale [Line Items]
Fair value		534.7	528.7		534.7
Four hundred million senior unsecured notes
Debt Securities, Available-for-sale [Line Items]
Carrying value		400.0	400.0		400.0
Four hundred million senior unsecured notes | Level 3
Debt Securities, Available-for-sale [Line Items]
Fair value		$ 372.0	$ 369.0		$ 372.0