Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2018	$ 2,672.4	$ 0.9	$ 494.5	$ 2,315.8	$ (138.8)
Beginning Balance (in shares) at Dec. 31, 2018		94,497
Common stock dividends declared	(74.8)	$ 0.0	0.0	(74.8)	0.0
Share-based compensation	6.9	$ 0.0	6.9	0.0	0.0
Share-based compensation expense (in shares)		(3)
Comprehensive income	190.1	$ 0.0	0.0	186.8	3.3
Ending Balance at Mar. 31, 2019	2,794.6	$ 0.9	501.4	2,427.8	(135.5)
Ending Balance (in shares) at Mar. 31, 2019		94,494
Beginning Balance at Dec. 31, 2019	3,071.0	$ 0.9	524.8	2,704.8	(159.5)
Beginning Balance (in shares) at Dec. 31, 2019		94,655
Common stock withheld and retired to cover taxes on vested stock awards	0.0	$ 0.0	0.0	0.0	0.0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(1)
Common stock dividends declared	(75.3)	$ 0.0	0.0	(75.3)	0.0
Share-based compensation	10.1	$ 0.0	10.1	0.0	0.0
Share-based compensation expense (in shares)		194
Other	(0.1)	$ 0.0	0.0	(0.1)	0.0
Comprehensive income	144.2	0.0	0.0	141.7	2.5
Ending Balance at Mar. 31, 2020	$ 3,149.9	$ 0.9	$ 534.9	$ 2,771.1	$ (157.0)
Ending Balance (in shares) at Mar. 31, 2020		94,848

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Common stock withheld to cover taxes on vested stock awards during the period.

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