Condensed Consolidating Financial Statements (Statements of Cash Flows) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	$ (83.5)	$ (107.6)
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment	0.1	0.1
Purchases of property, plant and equipment	(22.7)	(24.9)
Net cash used in investing activities	(22.6)	(24.8)
Cash flows from financing activities:
Short-term borrowings, net	(0.1)	(0.8)
Asset securitization borrowings	0.0	150.0
Asset securitization payments	(51.0)	0.0
Long-term debt payments	(10.2)	(0.2)
Long-term borrowings	0.0
Borrowings from credit facility	790.0	583.0
Payments on credit facility	(444.1)	(497.5)
Proceeds from employee stock purchases	0.8	0.7
Repurchases of common stock	(150.0)	(75.0)
Repurchases of common stock to satisfy employee withholding tax obligations	(18.1)	(13.3)
Intercompany debt	0.0	0.0
Intercompany financing activity	0.0	0.0
Cash dividends paid	(21.3)	(18.5)
Net cash provided by financing activities	96.0	128.4
Increase in cash and cash equivalents	(10.1)	(4.0)
Effect of exchange rates on cash and cash equivalents	(1.0)	2.6
Cash and cash equivalents, beginning of period	68.2	50.2
Cash and cash equivalents, end of period	57.1	48.8
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 cash used in investing activities	0.0	0.0
Cash flows from financing activities:
Short-term borrowings, net	0.0	0.0
Asset securitization borrowings	0.0	0.0
Asset securitization payments	0.0	0.0
Long-term debt payments	0.0	0.0
Long-term borrowings	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 debt	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
Increase 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
Cash and cash equivalents, end of period	0.0	0.0
Parent [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	104.4	341.2
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 cash used in investing activities	0.0	0.0
Cash flows from financing activities:
Short-term borrowings, net	0.0	0.0
Asset securitization borrowings	0.0	0.0
Asset securitization payments	0.0	0.0
Long-term debt payments	(7.5)	0.0
Long-term borrowings	0.0
Borrowings from credit facility	790.0	583.0
Payments on credit facility	(444.1)	(497.5)
Proceeds from employee stock purchases	0.8	0.7
Repurchases of common stock	(150.0)	(75.0)
Repurchases of common stock to satisfy employee withholding tax obligations	(18.1)	(13.3)
Intercompany debt	(47.5)	(29.3)
Intercompany financing activity	(206.9)	(291.0)
Cash dividends paid	(21.3)	(18.5)
Net cash provided by financing activities	(104.6)	(340.9)
Increase in cash and cash equivalents	(0.2)	0.3
Effect of exchange rates on cash and cash equivalents	0.0	0.0
Cash and cash equivalents, beginning of period	1.6	1.2
Cash and cash equivalents, end of period	1.4	1.5
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	(158.6)	(308.6)
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment	0.0	0.0
Purchases of property, plant and equipment	(17.3)	(22.0)
Net cash used in investing activities	(17.3)	(22.0)
Cash flows from financing activities:
Short-term borrowings, net	0.0	0.0
Asset securitization borrowings	0.0	0.0
Asset securitization payments	0.0	0.0
Long-term debt payments	(2.7)	(0.1)
Long-term borrowings	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 debt	37.9	7.6
Intercompany financing activity	127.7	320.0
Cash dividends paid	0.0	0.0
Net cash provided by financing activities	162.9	327.5
Increase in cash and cash equivalents	(13.0)	(3.1)
Effect of exchange rates on cash and cash equivalents	0.0	0.0
Cash and cash equivalents, beginning of period	28.0	17.1
Cash and cash equivalents, end of period	15.0	14.0
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	(29.3)	(140.2)
Cash flows from investing activities:
Proceeds from the disposal of property, plant and equipment	0.1	0.1
Purchases of property, plant and equipment	(5.4)	(2.9)
Net cash used in investing activities	(5.3)	(2.8)
Cash flows from financing activities:
Short-term borrowings, net	(0.1)	(0.8)
Asset securitization borrowings	0.0	150.0
Asset securitization payments	(51.0)	0.0
Long-term debt payments	0.0	(0.1)
Long-term borrowings	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 debt	9.6	21.7
Intercompany financing activity	79.2	(29.0)
Cash dividends paid	0.0	0.0
Net cash provided by financing activities	37.7	141.8
Increase in cash and cash equivalents	3.1	(1.2)
Effect of exchange rates on cash and cash equivalents	(1.0)	2.6
Cash and cash equivalents, beginning of period	38.6	31.9
Cash and cash equivalents, end of period	$ 40.7	$ 33.3