Income Taxes (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
Income Tax Examination [Line Items]
Material changes to the total amount of unrecognized tax benefits	$ 0
Accrued interest expense	79,000
Gross liability for unrecognized tax benefits	11,800,000
Unrecognized tax benefits that would impact our effective tax rate	7,500,000
Interest included in total liability	3,700,000
Significant increases or decreases for uncertain tax positions	0
State and Foreign Tax Authorities | Minimum
Income Tax Examination [Line Items]
Period of statute of limitations (years)	3 years
State and Foreign Tax Authorities | Maximum
Income Tax Examination [Line Items]
Period of statute of limitations (years)	4 years
IRS
Income Tax Examination [Line Items]
Estimated interest charges for unfavorable outcome	$ 2,100,000