Condensed Consolidating Financial Statements (Statements of Cash Flows) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities		$ (111.0)	$ (35.0)
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment		0.8	0.1
Purchases of property, plant and equipment		(53.5)	(43.4)
Net proceeds from sale of business and related property		43.6	111.8
Insurance recoveries received for property damage incurred from natural disaster		12.8
Payments to Acquire Short-term Investments		(1.8)	0.0
Net cash used in investing activities		1.9	68.5
Cash flows from financing activities:
Short-term debt payments		(2.1)	(18.4)
Asset securitization payments		(43.5)	(51.0)
Long-term debt payments		(33.3)	(17.8)
Borrowings from credit facility		1,459.5	1,391.0
Payments on credit facility		(1,037.5)	(1,042.0)
Proceeds from employee stock purchases		1.6	1.2
Repurchases of common stock		(250.0)	(350.2)
Repurchases of common stock to satisfy employee withholding tax obligations		(14.5)	(18.6)
Intercompany financing activity		0.0	0.0
Cash dividends paid		(50.8)	(42.4)
Net cash provided by financing activities		97.0	(61.9)
Decrease in cash and cash equivalents		(12.1)	(28.4)
Effect of exchange rates on cash and cash equivalents		2.2	(0.4)
Cash and cash equivalents, beginning of period	$ 39.4	46.3	68.2	$ 68.2
Cash and cash equivalents, end of period		36.4		46.3
Proceeds from Short-term Debt		(2.1)	(21.3)
Proceeds from Other Debt		65.5	65.0
Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities		0.0	0.0
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment		0.0	0.0
Purchases of property, plant and equipment		0.0	0.0
Net proceeds from sale of business and related property		0.0	0.0
Insurance recoveries received for property damage incurred from natural disaster		0.0
Payments to Acquire Short-term Investments		0.0
Net cash used in investing activities		0.0	0.0
Cash flows from financing activities:
Short-term debt payments		0.0	0.0
Asset securitization payments		0.0	0.0
Long-term debt payments		0.0	0.0
Borrowings from credit facility		0.0	0.0
Payments on credit facility		0.0	0.0
Proceeds from employee stock purchases		0.0	0.0
Repurchases of common stock		0.0	0.0
Repurchases of common stock to satisfy employee withholding tax obligations		0.0	0.0
Intercompany financing activity		0.0	0.0
Cash dividends paid		0.0	0.0
Net cash provided by financing activities		0.0	0.0
Decrease in cash and cash equivalents		0.0	0.0
Effect of exchange rates on cash and cash equivalents		0.0	0.0
Cash and cash equivalents, beginning of period	0.0	0.0	0.0	0.0
Cash and cash equivalents, end of period		0.0		0.0
Proceeds from Short-term Debt		0.0	0.0
Proceeds from Other Debt		0.0	0.0
Parent [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities		33.2	87.2
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment		0.0	0.0
Purchases of property, plant and equipment		0.0	0.0
Net proceeds from sale of business and related property		0.0	0.0
Insurance recoveries received for property damage incurred from natural disaster		0.0
Payments to Acquire Short-term Investments		0.0
Net cash used in investing activities		0.0	0.0
Cash flows from financing activities:
Short-term debt payments		0.0	0.0
Asset securitization payments		0.0	0.0
Long-term debt payments		(30.0)	(15.0)
Borrowings from credit facility		1,459.5	1,391.0
Payments on credit facility		(1,037.5)	(1,042.0)
Proceeds from employee stock purchases		1.6	1.2
Repurchases of common stock		(250.0)	(350.2)
Repurchases of common stock to satisfy employee withholding tax obligations		(14.5)	(18.6)
Intercompany financing activity		(111.4)	(11.2)
Cash dividends paid		(50.8)	(42.4)
Net cash provided by financing activities		(33.1)	(87.2)
Decrease in cash and cash equivalents		0.1	0.0
Effect of exchange rates on cash and cash equivalents		0.0	0.0
Cash and cash equivalents, beginning of period	1.6	1.8	1.6	1.6
Cash and cash equivalents, end of period		1.9		1.8
Proceeds from Short-term Debt		0.0	0.0
Proceeds from Other Debt		0.0	0.0
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities		(79.1)	(7.9)
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment		0.6	0.0
Purchases of property, plant and equipment		(49.2)	(33.0)
Net proceeds from sale of business and related property		43.0	0.0
Insurance recoveries received for property damage incurred from natural disaster		12.8
Payments to Acquire Short-term Investments		0.0
Net cash used in investing activities		7.2	(33.0)
Cash flows from financing activities:
Short-term debt payments		0.0	0.0
Asset securitization payments		0.0	0.0
Long-term debt payments		(1.9)	(2.7)
Borrowings from credit facility		0.0	0.0
Payments on credit facility		0.0	0.0
Proceeds from employee stock purchases		0.0	0.0
Repurchases of common stock		0.0	0.0
Repurchases of common stock to satisfy employee withholding tax obligations		0.0	0.0
Intercompany financing activity		80.3	38.2
Cash dividends paid		0.0	0.0
Net cash provided by financing activities		78.4	35.5
Decrease in cash and cash equivalents		6.5	(5.4)
Effect of exchange rates on cash and cash equivalents		0.4	0.0
Cash and cash equivalents, beginning of period	22.6	15.4	28.0	28.0
Cash and cash equivalents, end of period		22.3		15.4
Proceeds from Short-term Debt		0.0	0.0
Proceeds from Other Debt		0.0	0.0
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities		(65.1)	(114.3)
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment		0.2	0.1
Purchases of property, plant and equipment		(4.3)	(10.4)
Net proceeds from sale of business and related property		0.6	111.8
Insurance recoveries received for property damage incurred from natural disaster		0.0
Payments to Acquire Short-term Investments		(1.8)
Net cash used in investing activities		(5.3)	101.5
Cash flows from financing activities:
Short-term debt payments		(2.1)	(18.4)
Asset securitization payments		(43.5)	(51.0)
Long-term debt payments		(1.4)	(0.1)
Borrowings from credit facility		0.0	0.0
Payments on credit facility		0.0	0.0
Proceeds from employee stock purchases		0.0	0.0
Repurchases of common stock		0.0	0.0
Repurchases of common stock to satisfy employee withholding tax obligations		0.0	0.0
Intercompany financing activity		31.1	(27.0)
Cash dividends paid		0.0	0.0
Net cash provided by financing activities		51.7	(10.2)
Decrease in cash and cash equivalents		(18.7)	(23.0)
Effect of exchange rates on cash and cash equivalents		1.8	(0.4)
Cash and cash equivalents, beginning of period	$ 15.2	29.1	38.6	38.6
Cash and cash equivalents, end of period		12.2		$ 29.1
Proceeds from Short-term Debt		(2.1)	(21.3)
Proceeds from Other Debt		$ 65.5	$ 65.0