Commitments and Contingencies (Leases Commitments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 sqft
Operating Leased Assets [Line Items]
Aircraft hanger square feet	100,000
Cost of aircraft hanger	$ 15.7
Boeing 767 Aircraft [Member]
Operating Leased Assets [Line Items]
Number of leased aircrafts	6
Minimum [Member]
Operating Leased Assets [Line Items]
Construction of aircraft hanger period	12 months
Maximum [Member]
Operating Leased Assets [Line Items]
Construction of aircraft hanger period	14 months