Income Taxes Income Tax Contingency (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 3,000,000	$ 2,900,000	$ 3,200,000
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	1,512,000	1,149,000	4,668,000
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions	4,959,000	2,181,000	0
Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities	0	(555,000)	(1,449,000)
Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations	(2,430,000)	(1,113,000)	(869,000)
Unrecognized Tax Benefits	$ 14,027,000	$ 9,986,000	$ 8,324,000	$ 5,974,000