Significant Accounting Policies a (Tables)

9 Months Ended

Sep. 30, 2017

Accounting Policies [Abstract]

Property, Plant and Equipment Useful Life

Asset	Depreciable Lives	Principal Method
Telephone and computer equipment	3-5 years	Straight-line
Computer software	3-8 years	Straight-line
Furniture and fixtures	5 years	Straight-line
Leasehold improvements	2-15 years	Straight-line
Capitalized lease asset	5 years	Straight-line
Aircraft and related equipment	10-20 years	Straight-line
Modifications to aircraft	4-10 years	Straight-line