Commitments and Contingencies - Additional Information (Narrative) (Details)
12 Months Ended 0 Months Ended 12 Months Ended
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Dec. 31, 2012
USD ($)
Dec. 31, 2014
Environmental Remediation Matters
USD ($)
May 31, 2014
Fortis
USD ($)
May 31, 2014
Fortis
EUR (€)
Aug. 27, 2012
Fortis
USD ($)
Helicopter
Aug. 27, 2012
Fortis
EUR (€)
Aug. 31, 2012
Arizona
Sites
Parties
Dec. 31, 2014
Customer Relationships (EHI)
USD ($)
Dec. 31, 2013
Customer Relationships (EHI)
USD ($)
Loss Contingencies [Line Items]                      
First portion of cleanup costs to be borne by the former owner       $ 1,500,000              
Second portion of cleanup costs to be shared by the entity and former owner equally       1,000,000              
Cleanup costs, in excess of specified amount, to be borne by the former owner       2,500,000              
Loss contingencies, liability paid       400,000              
Entity's share of financial responsibility       500,000              
Remaining entity's share of financial responsibility liability       100,000              
Time frame to monitor the site       20 years              
Amount of damages for the payment of VAT levied             1,000,000 800,000      
Number of helicopters purchased from plaintiff             2 2      
Amount paid in final settlement         55,000 40,000          
Number of Alleged Cleanup Sites                 2    
Number of parties responsible for contamination                 101    
Accounts payable due   9,000,000                  
Operating Leases, Rent Expense 2,300,000 1,800,000 700,000             20,200,000 14,000,000
Outstanding Purchase Orders $ 29,600,000