Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Condensed Financial Statements
Net cash (used in) provided by operating activities	$ 101.1	$ 77.8
Cash flows from investing activities:
Capital expenditures	(51.2)	(72.1)
Distributions of capital on equity investments	1.5	3.8
Restricted cash	(0.6)	0.2
Changes in other assets and liabilities and other	1.5	(0.2)
Other, principally intercompany balances	0.0	0.0
Net cash used in investing activities	(48.8)	(68.3)
Cash flows from financing activities:
Net payments of long-term debt	(27.5)	(17.0)
Payments on license obligations	(9.6)	(9.0)
Net redemptions of common stock under stock-based compensation plans	0.0	(0.7)
Other, principally change in intercompany financing activities	0.0	0.0
Net cash provided by (used in) financing activities	(37.1)	(26.7)
Effect of exchange rate changes on cash and cash equivalents	1.8	(3.4)
Increase (decrease) in cash and cash equivalents	17.0	(20.6)
Cash and cash equivalents, beginning of period	128.7	171.8
Cash and cash equivalents, end of period	145.7	151.2
Parent Company
Condensed Financial Statements
Net cash (used in) provided by operating activities	(70.0)	59.9
Cash flows from investing activities:
Capital expenditures	(5.8)	(5.9)
Distributions of capital on equity investments	0.0	0.0
Restricted cash	0.0
Changes in other assets and liabilities and other	0.0
Other, principally intercompany balances	0.0	0.0
Net cash used in investing activities	(5.8)	(5.9)
Cash flows from financing activities:
Net payments of long-term debt	0.0	0.0
Payments on license obligations	(8.4)	(7.5)
Net redemptions of common stock under stock-based compensation plans		(0.7)
Other, principally change in intercompany financing activities	102.8	(26.0)
Net cash provided by (used in) financing activities	94.4	(34.2)
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Increase (decrease) in cash and cash equivalents	18.6	19.8
Cash and cash equivalents, beginning of period	43.2	37.9
Cash and cash equivalents, end of period	61.8	57.7
SGI
Condensed Financial Statements
Net cash (used in) provided by operating activities	88.7	45.8
Cash flows from investing activities:
Capital expenditures	(2.6)	(3.1)
Distributions of capital on equity investments	0.0	0.0
Restricted cash	0.0
Changes in other assets and liabilities and other	0.0
Other, principally intercompany balances	(60.3)	(26.2)
Net cash used in investing activities	(62.9)	(29.3)
Cash flows from financing activities:
Net payments of long-term debt	(25.8)	(15.8)
Payments on license obligations	0.0	0.0
Net redemptions of common stock under stock-based compensation plans		0.0
Other, principally change in intercompany financing activities	0.0	0.0
Net cash provided by (used in) financing activities	(25.8)	(15.8)
Effect of exchange rate changes on cash and cash equivalents	0.1	(0.5)
Increase (decrease) in cash and cash equivalents	0.1	0.2
Cash and cash equivalents, beginning of period	0.0	0.1
Cash and cash equivalents, end of period	0.1	0.3
Guarantor Subsidiaries
Condensed Financial Statements
Net cash (used in) provided by operating activities	57.7	(163.4)
Cash flows from investing activities:
Capital expenditures	(37.0)	(50.5)
Distributions of capital on equity investments	0.0	0.0
Restricted cash	(0.6)
Changes in other assets and liabilities and other	1.6
Other, principally intercompany balances	0.0	0.0
Net cash used in investing activities	(36.0)	(50.5)
Cash flows from financing activities:
Net payments of long-term debt	0.0	0.0
Payments on license obligations	(1.2)	(1.5)
Net redemptions of common stock under stock-based compensation plans		0.0
Other, principally change in intercompany financing activities	(22.9)	206.2
Net cash provided by (used in) financing activities	(24.1)	204.7
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Increase (decrease) in cash and cash equivalents	(2.4)	(9.2)
Cash and cash equivalents, beginning of period	4.7	28.8
Cash and cash equivalents, end of period	2.3	19.6
Non-Guarantor Subsidiaries
Condensed Financial Statements
Net cash (used in) provided by operating activities	24.7	135.5
Cash flows from investing activities:
Capital expenditures	(5.8)	(12.6)
Distributions of capital on equity investments	1.5	3.8
Restricted cash	0.0
Changes in other assets and liabilities and other	(0.1)
Other, principally intercompany balances	0.0	0.0
Net cash used in investing activities	(4.4)	(8.8)
Cash flows from financing activities:
Net payments of long-term debt	(1.7)	(1.2)
Payments on license obligations	0.0	0.0
Net redemptions of common stock under stock-based compensation plans		0.0
Other, principally change in intercompany financing activities	(19.6)	(154.0)
Net cash provided by (used in) financing activities	(21.3)	(155.2)
Effect of exchange rate changes on cash and cash equivalents	1.7	(2.9)
Increase (decrease) in cash and cash equivalents	0.7	(31.4)
Cash and cash equivalents, beginning of period	80.8	105.0
Cash and cash equivalents, end of period	81.5	73.6
Eliminating Entries
Condensed Financial Statements
Net cash (used in) provided by operating activities	0.0	0.0
Cash flows from investing activities:
Capital expenditures	0.0	0.0
Distributions of capital on equity investments	0.0	0.0
Restricted cash	0.0
Changes in other assets and liabilities and other	0.0
Other, principally intercompany balances	60.3	26.2
Net cash used in investing activities	60.3	26.2
Cash flows from financing activities:
Net payments of long-term debt	0.0	0.0
Payments on license obligations	0.0	0.0
Net redemptions of common stock under stock-based compensation plans		0.0
Other, principally change in intercompany financing activities	(60.3)	(26.2)
Net cash provided by (used in) financing activities	(60.3)	(26.2)
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Increase (decrease) in 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