CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Total revenue	$ 1,737.0	$ 1,613.1	$ 846.3
Operating expenses:
Salaries, wages and employee benefits	483.2	407.4	250.0
Fuel	138.5	141.1	93.7
Operations and maintenance	213.1	181.5	118.4
Communications	4.4	3.3	2.1
Administrative expenses	75.5	58.5	33.2
Sales and marketing	5.1	3.4	2.0
Taxes and licenses	19.2	17.2	11.0
Insurance and claims	49.9	45.8	24.0
Acquisition-related transaction expenses		2.6	3.4
Depreciation and amortization	146.5	131.1	76.9
Gain on disposition of revenue property and equipment	(5.2)	(3.2)	(0.7)
Impairment	312.8	13.9
Restructuring charges	8.4
Total operating expenses	2,049.1	1,591.2	839.3
Income (loss) from operations	(312.1)	21.9	7.0
Other expense (income):
Interest income	(1.0)	(1.3)	(0.4)
Interest expense	50.4	45.5	29.5
Write-off of unamortized deferred financing fees	2.3		3.9
Other	(1.8)	(1.2)	(0.7)
Total other expense	49.9	43.0	32.3
Loss before benefit for income taxes	(362.0)	(21.1)	(25.3)
Benefit for income taxes	(54.6)	(15.9)	(52.3)
Net income (loss)	(307.4)	(5.2)	27.0
Other comprehensive income:
Unrealized income on interest rate swaps			0.1
Foreign currency translation adjustments, net of tax expense (benefit) of $0.3, $(0.5) and $0.5, respectively	0.5	(1.8)	0.9
Comprehensive income (loss)	(306.9)	(7.0)	28.0
Net income (loss)	(307.4)	(5.2)	27.0
Net income (loss) attributable to common stockholders	$ (312.4)	$ (10.1)	$ 22.0
Net income (loss) per common share:
Basic (in dollars per share)	$ (4.86)	$ (0.16)	$ 0.59
Diluted (in dollars per share)	$ (4.86)	$ (0.16)	$ 0.56
Weighted-average common shares outstanding:
Basic (in shares)	64,303,438	61,654,820	37,592,549
Diluted (in shares)	64,303,438	61,654,820	39,593,701
Series A
Other comprehensive income:
Less dividends to convertible preferred stockholders	$ (5.0)	$ (4.9)	$ (4.2)
Weighted-average common shares outstanding:
Dividends declared per convertible preferred share	$ 7.63	$ 7.63	$ 6.40
Series B
Other comprehensive income:
Less dividends to convertible preferred stockholders			$ (0.8)
Weighted-average common shares outstanding:
Dividends declared per convertible preferred share			$ 12.50
Company freight
Revenues:
Total revenue	$ 804.6	$ 721.7	$ 460.8
Operating expenses:
Purchased freight	597.7	588.6	225.3
Owner operator freight
Revenues:
Total revenue	455.3	440.5	172.0
Brokerage
Revenues:
Total revenue	294.7	266.4	120.9
Logistics
Revenues:
Total revenue	47.5	42.8	22.1
Fuel
Revenues:
Total revenue	$ 134.9	$ 141.7	$ 70.5