Condensed Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings
Balance (in shares) at Dec. 31, 2018		165.3
Balance at Dec. 31, 2018	$ 2,832.2	$ 165.3	$ 2,247.4	$ (651.0)	$ 1,070.5
Lease accounting adoption adjustment	11.2	0.0	0.0	0.0	11.2
Net income (loss)	41.7	0.0	0.0	0.0	41.7
Other comprehensive (loss) income	(5.9)	0.0	0.0	(5.9)	0.0
Dividends paid:
Common stock ($0.20 per share)	(33.0)	$ 0.0	0.0	0.0	(33.0)
Common stock repurchased and retired (in shares)		(0.6)
Common stock repurchased and retired	$ (13.2)	$ (0.6)	(12.6)	0.0	0.0
Common stock issued for:
Stock options exercised (in shares)	0.1	0.1
Stock options exercised	$ 1.4	$ 0.1	1.3	0.0	0.0
Other transactions (in shares)		0.1
Other transactions	0.4	$ 0.1	0.3	0.0	0.0
Stock-based compensation	2.8	$ 0.0	2.8	0.0	0.0
Balance (in shares) at Mar. 31, 2019		164.9
Balance at Mar. 31, 2019	2,837.6	$ 164.9	2,239.2	(656.9)	1,090.4
Balance (in shares) at Dec. 31, 2019		157.7
Balance at Dec. 31, 2019	2,417.5	$ 157.7	2,122.1	(803.4)	941.1
Net income (loss)	(80.0)	0.0	0.0	0.0	(80.0)
Other comprehensive (loss) income	(17.7)	0.0	0.0	(17.7)	0.0
Dividends paid:
Common stock ($0.20 per share)	$ (31.5)	$ 0.0	0.0	0.0	(31.5)
Common stock issued for:
Stock options exercised (in shares)	0.1	0.0
Stock options exercised	$ 0.7	$ 0.0	0.7	0.0	0.0
Other transactions (in shares)		0.1
Other transactions	2.7	$ 0.1	2.6	0.0	0.0
Stock-based compensation	(2.6)	$ 0.0	(2.6)	0.0	0.0
Balance (in shares) at Mar. 31, 2020		157.8
Balance at Mar. 31, 2020	$ 2,289.1	$ 157.8	$ 2,122.8	$ (821.1)	$ 829.6