Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Freight revenue	$ 626,809	$ 610,845	$ 640,120
Fuel surcharge revenue	78,198	59,806	84,120
Total revenue	705,007	670,651	724,240
Operating expenses:
Salaries, wages, and related expenses	241,784	234,526	244,779
Fuel expense	103,139	103,108	122,160
Operations and maintenance	48,774	45,864	46,458
Revenue equipment rentals and purchased transportation	141,954	117,472	118,583
Operating taxes and licenses	9,878	11,712	11,016
Insurance and claims	33,155	32,596	31,909
Communications and utilities	6,938	6,057	6,162
General supplies and expenses	14,783	14,413	14,007
Depreciation and amortization, including gains and losses on disposition of property and equipment	76,447	72,456	61,384
Total operating expenses	676,852	638,204	656,458
Operating income	28,155	32,447	67,782
Interest expense, net	8,258	8,226	8,445
Income from equity method investment	(3,400)	(3,000)	(4,570)
Income before income taxes	23,297	27,221	63,907
Income tax (benefit) expense	(32,142)	10,386	21,822
Net income	$ 55,439	$ 16,835	$ 42,085
Income per share:
Basic income per share (in dollars per share)	$ 3.03	$ 0.93	$ 2.32
Diluted income per share (in dollars per share)	$ 3.02	$ 0.92	$ 2.30
Basic weighted average shares outstanding (in shares)	18,279	18,182	18,145
Diluted weighted average shares outstanding (in shares)	18,372	18,266	18,311

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Additionally, included are gains and losses on the sale of assets held for sale and property and equipment.

No definition available.