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, 2017	$ 2,182.6	$ 0.9	$ 471.2	$ 1,867.4	$ (156.9)
Beginning Balance (in shares) at Dec. 31, 2017		94,350
Common stock dividends declared	(59.5)	$ 0.0	0.0	(59.5)	0.0
Share-based compensation	5.1	$ 0.0	5.1	0.0	0.0
Share-based compensation expense (in shares)		(2)
Adoption of ASC 606 \| ASU 2014-09	1.6	$ 0.0	0.0	1.6	0.0
Comprehensive income	144.0	0.0	0.0	140.1	3.9
Ending Balance at Mar. 31, 2018	2,273.8	$ 0.9	476.3	1,949.6	(153.0)
Ending Balance (in shares) at Mar. 31, 2018		94,348
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

Amount of increase to additional paid-in capital (APIC) from recognition of equity-based compensation.

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