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Note 14 - Revenue and Business Segments - Operating Revenue and Operating Income by Segment (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Operating revenue: |  |  |
Operating revenue | $ 963,708 | $ 1,131,455 | $ 1,263,878
Operating expenses (income): |  |  |
Operating revenue | 963,708 | 1,131,455 | 1,263,878
Salaries, wages and benefits | 341,732 | 378,818 | 390,304
Purchased transportation | 169,142 | 199,334 | 249,792
Fuel and fuel taxes | 147,143 | 180,437 | 218,571
Supplies and maintenance | 63,337 | 67,411 | 55,700
Depreciation | 111,653 | 116,722 | 111,014
Operating taxes and licenses | 10,302 | 11,053 | 10,763
Operating income/(loss): |  |  |
Operating taxes and licenses | 10,302 | 11,053 | 10,763
Operating Income | 33,220 | 90,110 | 143,344
Insurance and claims | 53,109 | 56,014 | 50,513
Communications and utilities | 9,029 | 10,149 | 9,177
Other | 30,012 | 35,019 | 38,079
Total operating expenses | 930,488 | 1,041,345 | 1,120,534
Operating income | 33,220 | 90,110 | 143,344
Revenue Equipment [Member] |  |  |
Operating income/(loss): |  |  |
Gain on disposition of revenue equipment | (4,971) | (13,612) | (13,379)
Operating Segments [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 963,708 | 1,131,455 | 1,263,878
Operating expenses (income): |  |  |
Operating revenue | 963,708 | 1,131,455 | 1,263,878
Salaries, wages and benefits | 341,732 | 378,818 | 390,304
Purchased transportation | 169,142 | 199,334 | 249,792
Fuel and fuel taxes | 147,143 | 180,437 | 218,571
Supplies and maintenance | 63,337 | 67,411 | 55,700
Depreciation | 111,653 | 116,722 | 111,014
Operating taxes and licenses | 10,302 | 11,053 | 10,763
Operating income/(loss): |  |  |
Operating taxes and licenses | 10,302 | 11,053 | 10,763
Operating Income | 33,220 | 90,110 | 143,344
Insurance and claims | 53,109 | 56,014 | 50,513
Communications and utilities | 9,029 | 10,149 | 9,177
Other | 30,012 | 35,019 | 38,079
Total operating expenses | 930,488 | 1,041,345 | 1,120,534
Operating income | $ 33,220 | $ 90,110 | $ 143,344
Operating ratio | 0.966 | 0.92 | 0.887
Operating ratio, net of fuel surcharges | 0.96 | 0.907 | 0.864
Operating Segments [Member] | Revenue Equipment [Member] |  |  |
Operating income/(loss): |  |  |
Gain on disposition of revenue equipment | $ (4,971) | $ (13,612) | $ (13,379)
Truckload [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 439,792 | 465,475 | 500,462
Operating expenses (income): |  |  |
Operating revenue | 439,792 | 465,475 | 500,462
Operating income/(loss): |  |  |
Operating Income | 3,283 | 24,835 | 59,392
Operating income | 3,283 | 24,835 | 59,392
Truckload [Member] | Revenue, Net of Fuel Surcharge [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 377,452 | 395,565 | 411,448
Operating expenses (income): |  |  |
Operating revenue | 377,452 | 395,565 | 411,448
Truckload [Member] | Fuel Surcharge Revenue [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 62,340 | 69,910 | 89,014
Operating expenses (income): |  |  |
Operating revenue | 62,340 | 69,910 | 89,014
Truckload [Member] | Operating Segments [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 439,792 | 465,475 | 500,462
Operating expenses (income): |  |  |
Operating revenue | 439,792 | 465,475 | 500,462
Salaries, wages and benefits | 185,871 | 189,010 | 188,131
Purchased transportation | 4,520 | 4,958 | 4,835
Fuel and fuel taxes | 88,868 | 98,852 | 114,306
Supplies and maintenance | 39,925 | 37,495 | 30,495
Depreciation | 64,074 | 61,644 | 56,365
Operating taxes and licenses | 5,577 | 5,483 | 5,037
Operating income/(loss): |  |  |
Operating taxes and licenses | 5,577 | 5,483 | 5,037
Operating Income | 3,283 | 24,835 | 59,392
Insurance and claims | 29,693 | 28,460 | 25,848
Communications and utilities | 5,121 | 5,064 | 4,548
Other | 15,543 | 16,368 | 17,813
Total operating expenses | 436,509 | 440,640 | 441,070
Operating income | $ 3,283 | $ 24,835 | $ 59,392
Operating ratio | 0.993 | 0.947 | 0.881
Operating ratio, net of fuel surcharges | 0.991 | 0.937 | 0.856
Truckload [Member] | Operating Segments [Member] | Revenue Equipment [Member] |  |  |
Operating income/(loss): |  |  |
Gain on disposition of revenue equipment | $ (2,683) | $ (6,694) | $ (6,308)
Dedicated [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 319,135 | 408,272 | 429,092
Operating expenses (income): |  |  |
Operating revenue | 319,135 | 408,272 | 429,092
Operating income/(loss): |  |  |
Operating Income | 23,037 | 48,377 | 50,566
Operating income | 23,037 | 48,377 | 50,566
Dedicated [Member] | Revenue, Net of Fuel Surcharge [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 267,077 | 334,962 | 336,973
Operating expenses (income): |  |  |
Operating revenue | 267,077 | 334,962 | 336,973
Dedicated [Member] | Fuel Surcharge Revenue [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 52,058 | 73,310 | 92,119
Operating expenses (income): |  |  |
Operating revenue | 52,058 | 73,310 | 92,119
Dedicated [Member] | Operating Segments [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 319,135 | 408,272 | 429,092
Operating expenses (income): |  |  |
Operating revenue | 319,135 | 408,272 | 429,092
Salaries, wages and benefits | 137,340 | 165,257 | 172,179
Purchased transportation | 10,568 | 10,778 | 9,559
Fuel and fuel taxes | 52,925 | 73,083 | 91,091
Supplies and maintenance | 20,141 | 26,061 | 21,268
Depreciation | 39,452 | 46,151 | 45,630
Operating taxes and licenses | 4,066 | 4,881 | 4,855
Operating income/(loss): |  |  |
Operating taxes and licenses | 4,066 | 4,881 | 4,855
Operating Income | 23,037 | 48,377 | 50,566
Insurance and claims | 21,025 | 24,503 | 21,723
Communications and utilities | 2,861 | 3,727 | 3,471
Other | 9,831 | 11,758 | 15,136
Total operating expenses | 296,098 | 359,895 | 378,526
Operating income | $ 23,037 | $ 48,377 | $ 50,566
Operating ratio | 0.928 | 0.882 | 0.882
Operating ratio, net of fuel surcharges | 0.914 | 0.856 | 0.85
Dedicated [Member] | Operating Segments [Member] | Revenue Equipment [Member] |  |  |
Operating income/(loss): |  |  |
Gain on disposition of revenue equipment | $ (2,111) | $ (6,304) | $ (6,386)
Intermodal [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 58,754 | 92,078 | 129,765
Operating expenses (income): |  |  |
Operating revenue | 58,754 | 92,078 | 129,765
Operating income/(loss): |  |  |
Operating Income | (3,922) | (156) | 10,639
Operating income | (3,922) | (156) | 10,639
Intermodal [Member] | Revenue, Net of Fuel Surcharge [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 49,468 | 75,887 | 100,452
Operating expenses (income): |  |  |
Operating revenue | 49,468 | 75,887 | 100,452
Intermodal [Member] | Fuel Surcharge Revenue [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 9,286 | 16,191 | 29,313
Operating expenses (income): |  |  |
Operating revenue | 9,286 | 16,191 | 29,313
Intermodal [Member] | Operating Segments [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 58,754 | 92,078 | 129,765
Operating expenses (income): |  |  |
Operating revenue | 58,754 | 92,078 | 129,765
Salaries, wages and benefits | 11,028 | 17,666 | 21,602
Purchased transportation | 31,612 | 47,531 | 65,271
Fuel and fuel taxes | 5,350 | 8,502 | 13,174
Supplies and maintenance | 3,285 | 3,826 | 4,028
Depreciation | 6,076 | 7,071 | 7,493
Operating taxes and licenses | 330 | 470 | 516
Operating income/(loss): |  |  |
Operating taxes and licenses | 330 | 470 | 516
Operating Income | (3,922) | (156) | 10,639
Insurance and claims | 1,617 | 2,341 | 2,268
Communications and utilities | 223 | 359 | 412
Other | 3,332 | 5,082 | 5,047
Total operating expenses | 62,676 | 92,234 | 119,126
Operating income | $ (3,922) | $ (156) | $ 10,639
Operating ratio | 1.067 | 1.002 | 0.918
Operating ratio, net of fuel surcharges | 1.079 | 1.002 | 0.894
Intermodal [Member] | Operating Segments [Member] | Revenue Equipment [Member] |  |  |
Operating income/(loss): |  |  |
Gain on disposition of revenue equipment | $ (177) | $ (614) | $ (685)
Brokerage [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 146,027 | 165,630 | 204,559
Operating expenses (income): |  |  |
Operating revenue | 146,027 | 165,630 | 204,559
Operating income/(loss): |  |  |
Operating Income | 10,822 | 17,054 | 22,747
Operating income | 10,822 | 17,054 | 22,747
Brokerage [Member] | Operating Segments [Member] |  |  |
Operating revenue: |  |  |
Operating revenue | 146,027 | 165,630 | 204,559
Operating expenses (income): |  |  |
Operating revenue | 146,027 | 165,630 | 204,559
Salaries, wages and benefits | 7,493 | 6,885 | 8,392
Purchased transportation | 122,442 | 136,067 | 170,127
Fuel and fuel taxes | 0 | 0 | 0
Supplies and maintenance | (14) | 29 | (91)
Depreciation | 2,051 | 1,856 | 1,526
Operating taxes and licenses | 329 | 219 | 355
Operating income/(loss): |  |  |
Operating taxes and licenses | 329 | 219 | 355
Operating Income | 10,822 | 17,054 | 22,747
Insurance and claims | 774 | 710 | 674
Communications and utilities | 824 | 999 | 746
Other | 1,306 | 1,811 | 83
Total operating expenses | 135,205 | 148,576 | 181,812
Operating income | $ 10,822 | $ 17,054 | $ 22,747
Operating ratio | 0.926 | 0.897 | 0.889
Operating ratio, net of fuel surcharges | 0.926 | 0.897 | 0.889
Brokerage [Member] | Operating Segments [Member] | Revenue Equipment [Member] |  |  |
Operating income/(loss): |  |  |
Gain on disposition of revenue equipment | $ 0 | $ 0 | $ 0

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