Commitments and Contingencies (Future Payments) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Future minimum lease payments under noncancelable operating leases
2014	$ 47,097,000
2015	45,608,000
2016	42,876,000
2017	40,577,000
2018	38,626,000
Thereafter	285,146,000
Future minimum lease payments under noncancelable operating leases, Total	499,930,000
Expenses related to operating leases	57,500,000	61,600,000	60,200,000
Future noncancelable purchase commitments
2014	200,660,000
2015	139,540,000
2016	115,255,000
2017	117,663,000
2018	40,769,000
Thereafter	82,940,000
Future noncancelable purchase commitments, Total	$ 696,827,000
Credit agreement
Change of control provisions in debt covenants
Number of months considered to determine requirement of prepayment of debts	24 months
Lower Limit | Credit agreement
Change of control provisions in debt covenants
Debt instrument covenant, minimum percentage of ownership by a person	33.00%
Lower Limit | Debt Securities
Change of control provisions in debt covenants
Debt instrument covenant, minimum percentage of ownership by a person	50.00%