Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Income Taxes [Abstract]
Effective tax rate (in hundredths)			3.90%	36.80%
Discrete tax expense items			$ 3,600,000
Increase in unrecognized tax benefits associated with certain stock-based compensation items			1,100,000
Tax expense due to adjustment to unrecognized tax benefits associated with stock-based compensation items			2,500,000
Tax expense related to change in forward looking state rate			4,900,000
Decrease in unrecognized tax benefits in excess of prior year tax provision			900,000
Tax benefit derived from purchased entities			(5,000,000)
Tax benefit from reversal of tax reserves			(1,000,000)
Goodwill and intangible asset impairment	0	0	376,574,000	0
Impairment of goodwill and intangible assets that yielded permanent tax differences	255,000,000		255,000,000
Reduction in provision for income taxes			37,400,000
Reduction in previously recorded deferred tax liabilities	47,700,000		47,700,000
Annual estimated effective tax rate (in hundredths)	3.90%		3.90%
Gross unrecognized tax benefits	$ 2,000,000		$ 2,000,000		$ 1,700,000