Commitments and Contingencies (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015 sqft
Long-term Purchase Commitment [Line Items]
New Operating Lease Square Feet	16,085
Purchase commitments	$ 22,200,000
Standby Letters of Credit [Member]
Long-term Purchase Commitment [Line Items]
Number of irrevocable standby letters of credit	6
Maximum capacity to guarantee under existing letters of credit	6,400,000
Manufacturing and Service Agreement as Part of Asset Acquisition [Member]
Long-term Purchase Commitment [Line Items]
Purchase obligation, term	5 years
Minimum margin to be paid	25,000,000
Purchase commitments	$ 15,800,000