Consolidated Income Statements (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating revenue:
Revenue, excluding fuel surcharge revenue	$ 929,732	$ 954,974	$ 2,772,054	$ 2,785,737
Fuel surcharge revenue	83,494	109,999	220,849	353,784
Operating revenue	1,013,226	1,064,973	2,992,903	3,139,521
Operating expenses:
Salaries, wages, and employee benefits	293,098	283,767	868,831	821,747
Operating supplies and expenses	113,750	102,719	291,185	288,070
Fuel	90,464	103,023	252,822	326,598
Purchased transportation	280,041	299,866	830,952	883,354
Rental expense	57,004	59,088	170,326	180,909
Insurance and claims	47,372	52,877	140,888	139,390
Depreciation and amortization of property and equipment	67,245	66,852	198,884	184,194
Amortization of intangibles	4,204	4,204	12,611	12,611
Gain on disposal of property and equipment	(5,620)	(9,825)	(16,909)	(23,987)
Communication and utilities	7,130	8,236	20,977	23,134
Operating taxes and licenses	18,685	19,245	55,795	55,104
Total operating expenses	973,373	990,052	2,826,362	2,891,124
Operating income	39,853	74,921	166,541	248,397
Other expenses (income):
Interest expense	7,384	9,130	23,545	29,627
Derivative interest expense	0	68	0	3,972
Interest income	(624)	(647)	(2,011)	(1,825)
Loss on debt extinguishment	0	9,567	0	9,567
Non-cash impairments of non-operating assets	0	0	0	1,480
Legal settlements and reserves	0	0	3,000	6,000
Other income, net	(1,223)	(752)	(3,093)	(2,341)
Total other expenses (income), net	5,537	17,366	21,441	46,480
Income before income taxes	34,316	57,555	145,100	201,917
Income tax expense	10,292	21,274	46,275	76,842
Net income	$ 24,024	$ 36,281	$ 98,825	$ 125,075
Basic earnings per share	$ 0.18	$ 0.25	$ 0.73	$ 0.88
Diluted earnings per share	$ 0.18	$ 0.25	$ 0.73	$ 0.87
Shares used in per share calculations
Basic	132,930	142,801	134,622	142,535
Diluted	134,462	144,132	136,227	144,238