XML 56 R40.htm IDEA: XBRL DOCUMENT v3.7.0.1
Summary of Financial Statement Preparation and Significant Accounting Policies (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2016
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Line Items]        
Excess Tax Benefit from Share-based Compensation, Financing Activities $ 0.7 $ 1.2 $ 0.8  
Capitalized interest   1.3 0.2 $ 0.1
Other liabilities for self-insured reserves   $ 18.7 $ 23.3  
Minimum [Member] | Ground equipment [Member]        
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Line Items]        
Property, plant and equipment, useful life   3 years    
Minimum [Member] | facilities, leasehold improvements and office equipment [Member]        
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Line Items]        
Property, plant and equipment, useful life   3 years    
Maximum [Member] | Ground equipment [Member]        
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Line Items]        
Property, plant and equipment, useful life   10 years    
Maximum [Member] | facilities, leasehold improvements and office equipment [Member]        
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Line Items]        
Property, plant and equipment, useful life   25 years    
Boeing 767 and 757 aircraft and flight equipment [Member] | Minimum [Member] | Flight Equipment [Member]        
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Line Items]        
Property, plant and equipment, useful life   10 years    
Boeing 767 and 757 aircraft and flight equipment [Member] | Maximum [Member] | Flight Equipment [Member]        
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Line Items]        
Property, plant and equipment, useful life   18 years