Income Taxes (Details Textual) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 31, 2011	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015
Income Tax Contingency [Line Items]
Effective tax rate		23.90%	27.00%	24.70%	26.90%
Notice of assessment of corporate withholding tax including penalties and interest						$ 48.3
Net benefit for a previously unrecognized position		$ 24.0		$ 24.0
Tax Year 2007
Income Tax Contingency [Line Items]
Proposed deduction disallowance by tax authorities	$ 130.0
Tax Year 2008
Income Tax Contingency [Line Items]
Proposed deduction disallowance by tax authorities	130.0
Tax Year 2009
Income Tax Contingency [Line Items]
Proposed deduction disallowance by tax authorities	$ 130.0