Condensed Consolidated Statements of Changes in Equity - USD ($) shares in Thousands, $ in Millions	Total	Ordinary shares	Additional paid-in capital	Retained earnings	Accumulated other comprehensive (loss) income
Dividends (in dollars per share)	$ 0.22
Beginning Balance (in shares) at Dec. 31, 2022		164,500
Beginning Balance at Dec. 31, 2022	$ 2,708.1	$ 1.7	$ 1,554.9	$ 1,390.5	$ (239.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	129.7			129.7
Other comprehensive loss, net of tax	4.9				4.9
Dividends declared	(36.3)			(36.3)
Exercise of options, net of shares tendered for payment (in shares)		100
Exercise of options, net of shares tendered for payment	2.5		2.5
Issuance of restricted shares, net of cancellations (in shares)		(500)
Issuance of restricted shares, net of cancellations	(2.3)		(2.3)
Shares surrendered by employees to pay taxes (in shares)		(100)
Shares surrendered by employees to pay taxes	(4.3)		(4.3)
Share-based compensation	7.2		7.2
Ending Balance (in shares) at Mar. 31, 2023		165,000
Ending Balance at Mar. 31, 2023	2,809.5	$ 1.7	1,558.0	1,483.9	(234.1)
Beginning Balance (in shares) at Dec. 31, 2022		164,500
Beginning Balance at Dec. 31, 2022	2,708.1	$ 1.7	1,554.9	1,390.5	(239.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	282.6
Ending Balance (in shares) at Jun. 30, 2023		165,100
Ending Balance at Jun. 30, 2023	$ 2,935.3	$ 1.7	1,569.8	1,600.4	(236.6)
Dividends (in dollars per share)	$ 0.22
Beginning Balance (in shares) at Mar. 31, 2023		165,000
Beginning Balance at Mar. 31, 2023	$ 2,809.5	$ 1.7	1,558.0	1,483.9	(234.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	152.9			152.9
Other comprehensive loss, net of tax	(2.5)				(2.5)
Dividends declared	(36.4)			(36.4)
Exercise of options, net of shares tendered for payment (in shares)		100
Exercise of options, net of shares tendered for payment	6.3		6.3
Shares surrendered by employees to pay taxes	(1.4)		(1.4)
Share-based compensation	6.9		6.9
Ending Balance (in shares) at Jun. 30, 2023		165,100
Ending Balance at Jun. 30, 2023	$ 2,935.3	$ 1.7	1,569.8	1,600.4	(236.6)
Dividends (in dollars per share)	$ 0.23
Beginning Balance (in shares) at Dec. 31, 2023		165,300
Beginning Balance at Dec. 31, 2023	$ 3,217.1	$ 1.7	1,593.6	1,866.2	(244.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	133.3			133.3
Other comprehensive loss, net of tax	1.0				1.0
Dividends declared	(38.2)			(38.2)
Exercise of options, net of shares tendered for payment (in shares)		400
Exercise of options, net of shares tendered for payment	15.2		15.2
Issuance of restricted shares, net of cancellations (in shares)		(400)
Issuance of restricted shares, net of cancellations	(4.0)		(4.0)
Shares surrendered by employees to pay taxes (in shares)		(100)
Shares surrendered by employees to pay taxes	(5.1)		(5.1)
Share-based compensation	7.9		7.9
Ending Balance (in shares) at Mar. 31, 2024		166,000
Ending Balance at Mar. 31, 2024	3,327.2	$ 1.7	1,607.6	1,961.3	(243.4)
Beginning Balance (in shares) at Dec. 31, 2023		165,300
Beginning Balance at Dec. 31, 2023	3,217.1	$ 1.7	1,593.6	1,866.2	(244.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 319.4
Share repurchase (in shares)	(600)
Share repurchases	$ (50.0)
Ending Balance (in shares) at Jun. 30, 2024		165,500
Ending Balance at Jun. 30, 2024	$ 3,432.9	$ 1.7	1,569.2	2,109.3	(247.3)
Dividends (in dollars per share)	$ 0.23
Beginning Balance (in shares) at Mar. 31, 2024		166,000
Beginning Balance at Mar. 31, 2024	$ 3,327.2	$ 1.7	1,607.6	1,961.3	(243.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	186.1			186.1
Other comprehensive loss, net of tax	(3.9)				(3.9)
Dividends declared	$ (38.1)			(38.1)
Share repurchase (in shares)	(600)	(600)
Share repurchases	$ (50.0)		(50.0)
Exercise of options, net of shares tendered for payment (in shares)		100
Exercise of options, net of shares tendered for payment	3.7		3.7
Shares surrendered by employees to pay taxes	(0.5)		(0.5)
Share-based compensation	8.4		8.4
Ending Balance (in shares) at Jun. 30, 2024		165,500
Ending Balance at Jun. 30, 2024	$ 3,432.9	$ 1.7	$ 1,569.2	$ 2,109.3	$ (247.3)