Seat Licenses And Other Intangible Assets (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Capital lease term	3 years
Seat Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 0.5	$ 0.5
Capital leases used to purchase seat licenses	0.1
Estimated useful life	5 years
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 0.9	$ 0.9
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	15 years
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	3 years