Income Taxes (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Jun. 08, 2010
Income Taxes (Textual) [Abstract]
Effective tax rate	24.40%	23.80%	19.60%	22.70%
Deferred tax liability recognized	$ 203.7
Net benefit for a previously unrecognized position	33.0		33.0
Expense for non-income based state taxes	10.0		10.0
Net benefit from remeasurement of uncertain tax position	7.4		7.4
Proposed deduction disallowance by tax authorities					130	130	130
Notice of Assessment of corporate excise tax including penalties and interest								$ 103.5