Income Taxes (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income Tax Contingency [Line Items]
Tax benefit recognized on changes in net state tax reserves		$ 1.5		$ 1.8
Adjustment to net deferred tax liability for state tax filing responsibilities	5.1
Additions for tax positions related to the current year			3.4	3.1
Additions for tax positions of prior years			1.9	0
Reductions for tax positions of prior years			0	1.1
Unrecognized tax benefits including interest and penalties that would affect the Company's effective tax rate if recognized	13.9	15.9	13.9	15.9
Total accrued interest and penalties	11.0		11.0		10.3
Increase (decrease) in income tax expense related to interest and penalties on unrecognized tax benefits	0.2	(1.3)	0.7	(2.1)
Lapse in Statute of Limitations
Income Tax Contingency [Line Items]
Reasonably possible change to unrecognized tax benefits within twelve months	$ 4.5		$ 4.5
Swiss subsidiary
Income Tax Contingency [Line Items]
Number of subsidiaries			2
General period of statute of limitations in Switzerland			5 years
Extended period of statute of limitations in Switzerland			15 years