Significant Accounting Policies (Details 7) In Millions, unless otherwise specified	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2015 Interest rate swap USD ($) DerivativeInstrument	Dec. 31, 2014 Interest rate swap USD ($) DerivativeInstrument	Mar. 31, 2015 Interest rate swap Other liabilities. USD ($)	Dec. 31, 2014 Interest rate swap Other liabilities. USD ($)	Dec. 31, 2014 Interest rate swap Deferred costs and other assets USD ($)	Mar. 31, 2015 USD-Yen currency forward contract JPY (¥)	Dec. 31, 2014 USD-Yen currency forward contract JPY (¥)	Mar. 31, 2015 USD-Yen currency forward contract Deferred costs and other assets USD ($)	Dec. 31, 2014 USD-Yen currency forward contract Deferred costs and other assets USD ($)	Sep. 30, 2014 USD-Euro currency forward contract EUR (€)	Mar. 31, 2015 USD-Euro currency forward contract Deferred costs and other assets USD ($)	Dec. 31, 2014 USD-Euro currency forward contract Deferred costs and other assets USD ($)
Derivative financial instruments
Number of Instruments			2	2
Notional Amount			$ 375.0	$ 375.0				¥ 1,900.0	¥ 14.7			€ 150.0
Interest rate net, fair value				(1.2)	(12.3)	(2.1)	0.9
Forward contract net, fair value										0.3	0.1		39.8	19.1
Gross accumulated other comprehensive income or loss related to derivative activities	$ 33.1	$ 45.8