Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

Summary of Company's Property and Equipment

The following table summarizes the Company’s property and equipment at December 31 of the following years:

	2018			2017
	(Thousands of dollars)
Flight equipment	$	1,227,341		$	1,225,205
Facility & improvements	67,784			64,316
Operating equipment	30,832			29,913
Data processing equipment	35,889			34,747
Vehicles	3,798			8,202
Medical equipment	8,710			8,354
Other	6,056			6,523
	1,380,410			1,377,260
Less accumulated depreciation and amortization	(477,925		)	(430,495		)
Property and equipment, net	$	902,485		$	946,765