Changes to Significant Accounting Policies Narrative (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Change in Accounting Estimate [Line Items]
Property and equipment useful life minimum (in years)		1 year
Property and equipment per unit value minimum	$ 1,000	$ 1,000
Service Life [Member]
Change in Accounting Estimate [Line Items]
Change in accounting estimate, financial impact	$ 10,300,000	$ 37,200,000
Software and Hardware [Member] | Historical Useful Life [Member]
Change in Accounting Estimate [Line Items]
Property and equipment useful life (in years)		3 years
Software and Hardware [Member] | Service Life [Member]
Change in Accounting Estimate [Line Items]
Property and equipment useful life (in years)		4 years