Fair Value Measurements (Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Cost method investments	$ 24,300,000	$ 26,200,000
Cost method investments, fair value of impaired investment	5,600,000	9,500,000
Cost method investment, impairment charge	3,700,000	3,500,000	3,500,000
Impaired investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Cost method investments	9,300,000	13,000,000
Convertible debt securities | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2012	3,341,000
Purchases of Level 3 securities	9,700,000
Transfers out of Level 3	(2,750,000)
Balance at December 31, 2013	$ 10,291,000