Commitments and Contingencies (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Future minimum lease payments under noncancelable operating leases
2013	$ 65,929,000
2014	60,357,000
2015	58,206,000
2016	55,547,000
2017	52,796,000
Thereafter	338,113,000
Future minimum lease payments under noncancelable operating leases, Total	630,948,000
Expenses related to operating leases	61,600,000	60,200,000	50,800,000
Future noncancelable purchase commitments
2013	231,137,000
2014	144,288,000
2015	128,805,000
2016	83,603,000
2017	94,631,000
Thereafter	96,648,000
Future noncancelable purchase commitments, Total	$ 779,112,000
Line of Credit
Change of control provisions in debt covenants
Number of months considered to determine requirement of prepayment of debts	24 months
Line of Credit | Minimum
Change of control provisions in debt covenants
Debt instrument covenant, minimum percentage of ownership by a person	33.00%
Debt Securities | Minimum
Change of control provisions in debt covenants
Debt instrument covenant, minimum percentage of ownership by a person	50.00%