Income Taxes Income Taxes (Unrecognized Tax Benefits) (Details) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Income Tax Contingency [Line Items]
Increase to stockholders equity if stock based compensation tax benefits are realized	$ 87,100,000
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	8,376,000	9,255,000
Additions based on current year tax positions	10,808,000	2,334,000
Reductions as a result of the lapse of statute limitations	0	(3,213,000)
Balance at end of year	$ 19,184,000	$ 8,376,000