Condensed Consolidating Financial Statements (Statements of Cash Flows) (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	$ 124.5	$ 231.3
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment	1.2	0.1
Purchases of property, plant and equipment	(77.0)	(60.9)
Net proceeds from sale of business and related property	43.5	115.9
Insurance recoveries received for property damage incurred from natural disaster	11.6	4.2
Payments to Acquire Short-term Investments	(2.4)	0.0
Net cash used in investing activities	(23.1)	59.3
Cash flows from financing activities:
Short-term debt payments	(5.3)	(41.1)
Asset securitization payments	(58.0)	(53.7)
Long-term debt payments	(35.0)	(32.9)
Proceeds from Issuance of Long-term Debt		0.0
Borrowings from credit facility	1,938.5	1,820.0
Payments on credit facility	(1,608.5)	(1,766.5)
Proceeds from employee stock purchases	2.5	2.5
Repurchases of common stock	(400.0)	(350.2)
Repurchases of common stock to satisfy employee withholding tax obligations	(16.9)	(21.1)
Intercompany financing activity	0.0	0.0
Cash dividends paid	(80.9)	(68.2)
Net cash provided by financing activities	(102.8)	(316.6)
Decrease in cash and cash equivalents	(1.4)	(26.0)
Effect of exchange rates on cash and cash equivalents	1.2	3.9
Cash and cash equivalents, beginning of period	46.3	68.2	$ 68.2
Cash and cash equivalents, end of period	46.1	46.1	46.3
Proceeds from Short-term Debt	(5.3)	(39.6)
Proceeds from Other Debt	155.5	155.0
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
Proceeds from Issuance of Long-term Debt		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
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	21.0	57.2
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)	(30.0)
Proceeds from Issuance of Long-term Debt		0.0
Borrowings from credit facility	1,938.5	1,820.0
Payments on credit facility	(1,608.5)	(1,766.5)
Proceeds from employee stock purchases	2.5	2.5
Repurchases of common stock	(400.0)	(350.2)
Repurchases of common stock to satisfy employee withholding tax obligations	(16.9)	(21.1)
Intercompany financing activity	173.9	356.1
Cash dividends paid	(80.9)	(68.2)
Net cash provided by financing activities	(21.4)	(57.4)
Decrease in cash and cash equivalents	(0.4)	(0.2)
Effect of exchange rates on cash and cash equivalents	0.0	0.0
Cash and cash equivalents, beginning of period	1.8	1.6	1.6
Cash and cash equivalents, end of period	1.4		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	217.7	362.5
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment	0.8	0.0
Purchases of property, plant and equipment	(71.6)	(46.1)
Net proceeds from sale of business and related property	42.9	4.0
Insurance recoveries received for property damage incurred from natural disaster	11.6
Payments to Acquire Short-term Investments	0.0
Net cash used in investing activities	(16.3)	(37.9)
Cash flows from financing activities:
Short-term debt payments	0.0	0.0
Asset securitization payments	0.0	0.0
Long-term debt payments	(3.0)	(2.8)
Proceeds from Issuance of Long-term Debt		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	(188.2)	(323.0)
Cash dividends paid	0.0	0.0
Net cash provided by financing activities	(191.2)	(325.8)
Decrease in cash and cash equivalents	10.2	(1.2)
Effect of exchange rates on cash and cash equivalents	0.4	(2.8)
Cash and cash equivalents, beginning of period	15.4	28.0	28.0
Cash and cash equivalents, end of period	26.0		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	(114.2)	(188.4)
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment	0.4	0.1
Purchases of property, plant and equipment	(5.4)	(14.8)
Net proceeds from sale of business and related property	0.6	111.9
Insurance recoveries received for property damage incurred from natural disaster	0.0
Payments to Acquire Short-term Investments	(2.4)
Net cash used in investing activities	(6.8)	97.2
Cash flows from financing activities:
Short-term debt payments	(5.3)	(41.1)
Asset securitization payments	(58.0)	(53.7)
Long-term debt payments	(2.0)	(0.1)
Proceeds from Issuance of Long-term Debt		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	14.3	(33.1)
Cash dividends paid	0.0	0.0
Net cash provided by financing activities	109.8	66.6
Decrease in cash and cash equivalents	(11.2)	(24.6)
Effect of exchange rates on cash and cash equivalents	0.8	6.7
Cash and cash equivalents, beginning of period	29.1	38.6	38.6
Cash and cash equivalents, end of period	18.7		$ 29.1
Proceeds from Short-term Debt	(5.3)	(39.6)
Proceeds from Other Debt	$ 155.5	$ 155.0