Investments - Other Investments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Other investments	$ 11,012	$ 34,215
Fair Value, Measurements, Recurring
Schedule of Investments [Line Items]
Other investments	11,012	34,215
Fair Value, Measurements, Recurring | Iridium [Member]
Schedule of Investments [Line Items]
Other investments	10,978	34,165
Fair Value, Measurements, Recurring | Deferred Compensation Plan Investments [Member]
Schedule of Investments [Line Items]
Other investments	34	50
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Schedule of Investments [Line Items]
Other investments	10,978	34,165
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Iridium [Member]
Schedule of Investments [Line Items]
Other investments	10,978	34,165
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Deferred Compensation Plan Investments [Member]
Schedule of Investments [Line Items]
Other investments	0	0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Schedule of Investments [Line Items]
Other investments	34	50
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Iridium [Member]
Schedule of Investments [Line Items]
Other investments	0	0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Deferred Compensation Plan Investments [Member]
Schedule of Investments [Line Items]
Other investments	$ 34	$ 50