Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2021	$ 3,607.2	$ 0.9	$ 579.4	$ 3,102.1	$ (75.2)
Beginning Balance (in shares) at Dec. 31, 2021		93,539,000
Common stock withheld and retired to cover taxes on vested stock awards	(9.5)		(0.6)	(8.9)
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(67,000)
Common stock dividends declared	(211.9)			(211.9)
Share-based compensation and other	22.2		22.2
Share-based compensation and other (in shares)		214,000
Comprehensive income	556.5			555.7	0.8
Ending Balance at Jun. 30, 2022	3,964.5	$ 0.9	601.0	3,437.0	(74.4)
Ending Balance (in shares) at Jun. 30, 2022		93,686,000
Beginning Balance at Mar. 31, 2022	3,779.3	$ 0.9	591.7	3,261.9	(75.2)
Beginning Balance (in shares) at Mar. 31, 2022		93,704,000
Common stock withheld and retired to cover taxes on vested stock awards	(9.2)		(0.5)	(8.7)
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(66,000)
Common stock dividends declared	(117.7)			(117.7)
Share-based compensation and other	9.8		9.8
Share-based compensation and other (in shares)		48,000
Comprehensive income	302.3			301.5	0.8
Ending Balance at Jun. 30, 2022	3,964.5	$ 0.9	601.0	3,437.0	(74.4)
Ending Balance (in shares) at Jun. 30, 2022		93,686,000
Beginning Balance at Dec. 31, 2022	3,667.1	$ 0.9	581.8	3,186.8	(102.4)
Beginning Balance (in shares) at Dec. 31, 2022		89,695,000
Common stock withheld and retired to cover taxes on vested stock awards	(15.6)		(1.1)	(14.5)
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(119,000)
Common stock dividends declared	(226.1)			(226.1)
Share-based compensation and other	26.7		26.7
Share-based compensation and other (in shares)		340,000
Comprehensive income	396.5			392.8	3.7
Ending Balance at Jun. 30, 2023	3,848.6	$ 0.9	607.4	3,339.0	(98.7)
Ending Balance (in shares) at Jun. 30, 2023		89,916,000
Beginning Balance at Mar. 31, 2023	3,757.7	$ 0.9	597.8	3,259.3	(100.3)
Beginning Balance (in shares) at Mar. 31, 2023		89,932,000
Common stock withheld and retired to cover taxes on vested stock awards	(10.8)		(0.7)	(10.1)
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(83,000)
Common stock dividends declared	(112.9)			(112.9)
Share-based compensation and other	10.3		10.3
Share-based compensation and other (in shares)		67,000
Comprehensive income	204.3			202.7	1.6
Ending Balance at Jun. 30, 2023	$ 3,848.6	$ 0.9	$ 607.4	$ 3,339.0	$ (98.7)
Ending Balance (in shares) at Jun. 30, 2023		89,916,000