Income Taxes (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reconciliation of beginning and ending balance of unrecognized tax benefits
Balance at the beginning of the period	$ 49,396,000	$ 49,587,000	$ 47,875,000
Increases related to current year tax positions	2,046,000	300,000	780,000
Increases related to prior year tax positions	13,785,000	1,361,000	5,099,000
Decreases related to prior year tax positions	(196,000)	(496,000)	(3,766,000)
Lapses in statutes of limitations		(1,128,000)	(401,000)
Settlements with taxing authorities	(476,000)	(228,000)
Balance at the end of the period	64,555,000	49,396,000	49,587,000
Unrecognized tax benefits that, if recognized, would impact effective tax rate	24,600,000
Interest expenses, net of tax	3,100,000
Penalties	(35,000)
Accrued interest and penalties	16,100,000
Internal Revenue Service (IRS)
Income tax examinations
Expected payment of taxes as a result of audit settlement, lower bound	0
Expected payment of taxes as a result of audit settlement, upper bound	$ 2,300,000