v3.3.1.900
Summary of Significant Accounting Policies - Additional Information (Detail)
 3 Months Ended 12 Months Ended
Sep. 29, 2012
Dec. 31, 2015
USD ($)
Sep. 30, 2015
USD ($)
Jun. 30, 2015
USD ($)
Mar. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Sep. 30, 2014
USD ($)
Jun. 30, 2014
USD ($)
Mar. 31, 2014
USD ($)
Dec. 31, 2015
USD ($)
Aircraft
Dec. 31, 2014
USD ($)
Aircraft
Dec. 31, 2013
USD ($)
Aircraft
Summary Of Significant Accounting Policies [Line Items]                        
Percentage of stock owned by CEO                   70.20%    
Maturities Period of liquid investments                   Three months or less    
Valuation reserves related to obsolescence and slow moving inventory   $ 15,400,000       $ 13,500,000       $ 15,400,000 $ 13,500,000  
Gain or loss on sale of assets   (577,000) $ 165,000 $ 66,000 $ 7,000 523,000 $ (56,000) $ (242,000) $ (1,073,000) (339,000) (848,000) $ 16,604,000
Impairments of assets                     10,508,000 1,648,000
Insurance retention per claim                   250,000    
Accrued liabilities related to health care claims   1,900,000       1,700,000       1,900,000 1,700,000  
Amount deductible per incident                   500,000    
Accrued expense related to workers compensation claims   2,600,000       2,500,000       2,600,000 2,500,000  
Amounts paid to offshore insurance captive                   1,000,000 900,000  
Allowance for contractual discounts against outstanding accounts receivable   103,600,000       96,600,000       103,600,000 96,600,000 74,700,000
Allowance for uncompensated care against outstanding accounts receivable   41,900,000       41,900,000       41,900,000 41,900,000 46,400,000
Value of uncompensated care services   9,300,000       9,100,000       9,300,000 9,100,000 7,900,000
Estimated cost of providing charity services   $ 2,000,000       $ 2,100,000       $ 2,000,000 $ 2,100,000 $ 3,000,000
Percentage of reserved category of self pay                   100.00%    
Percentage of consolidated operating revenues                   26.00% 30.00% 28.00%
Percentage of trade receivables   15.00%       18.00%       15.00% 18.00%  
Debt issuance cost                   $ 4,000,000 $ 5,200,000  
Maximum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Unrealized losses recorded                   (900,000)    
Medium Aircraft [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Carrying value of aircraft           $ 16,500,000         16,500,000 $ 4,000,000
Market value of aircraft           6,000,000         6,000,000 2,400,000
Impairments of assets                   0 10,500,000 $ 1,600,000
Oil and Gas [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Carrying value of aircraft   $ 3,700,000       5,500,000       3,700,000 5,500,000  
Cash realized from sale of assets                   3,700,000 5,900,000  
Gain or loss on sale of assets                   $ 0 $ 400,000  
Oil and Gas [Member] | Light Aircraft [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Number of aircraft sold | Aircraft                   8 9  
Oil and Gas [Member] | Medium Aircraft [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Number of aircraft sold | Aircraft                   6    
Number of Aircraft impaired | Aircraft                     13 2
Oil and Gas [Member] | Fixed Wing Aircraft [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Number of aircraft sold | Aircraft                     3  
Air Medical [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Carrying value of aircraft           10,800,000         $ 10,800,000  
Cash realized from sale of assets                     8,200,000  
Gain or loss on sale of assets                     (2,600,000)  
Allowance for contractual discounts against outstanding accounts receivable   103,600,000       96,600,000       $ 103,600,000 96,600,000 $ 74,700,000
Allowance for uncompensated care against outstanding accounts receivable   41,900,000       41,900,000       41,900,000 $ 41,900,000 $ 46,400,000
Term of contract for providing products and services to a customer in Middle East 3 years                      
Air Medical [Member] | Light Aircraft [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Number of aircraft sold | Aircraft                     4  
Air Medical [Member] | Medium Aircraft [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Number of aircraft sold | Aircraft                     1  
Number of Aircraft impaired | Aircraft                     1 2
Oil and Gas and Technical Services segments [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Allowance for doubtful accounts   $ 3,200,000       $ 100,000       $ 3,200,000 $ 100,000  
Air Medical and Technical Services [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Percentage of consolidated operating revenues                   9.00% 10.00%  
Percentage of trade receivables   15.00%       20.00%       15.00% 20.00%  
Aircraft [Member] | Maximum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Salvage value of aircraft   54.00%               54.00%    
Aircraft [Member] | Minimum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Salvage value of aircraft   25.00%               25.00%    
Flight Equipment [Member] | Maximum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Estimated useful life                   15 years    
Flight Equipment [Member] | Minimum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Estimated useful life                   5 years    
Other equipment [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Gain or loss on sale of assets                     $ 1,400,000  
Other equipment [Member] | Maximum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Estimated useful life                   10 years    
Other equipment [Member] | Minimum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Estimated useful life                   3 years    
Leasehold improvements [Member] | Maximum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Estimated useful life                   10 years    
Leasehold improvements [Member] | Minimum [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Estimated useful life                   6 years    
Spare Parts Inventory [Member]                        
Summary Of Significant Accounting Policies [Line Items]                        
Gain or loss on sale of assets                   $ (300,000)