INCOME TAXES - Deferred income taxes (Details) - USD ($) $ in Thousands	2 Months Ended	10 Months Ended	12 Months Ended
Feb. 28, 2018	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of the deferred tax provision or benefit
Amortization, depreciation, and basis differences for property, plant and equipment and other long-lived assets			$ 4,975	$ 16,255	$ 23,153
Amortization of intangibles and impairment			183	(6,933)	(763)
Changes in reserves for workers' compensation, third-party casualty, and cargo claims			(182)	(1,880)	469
Revenue recognition			(1,481)	(1,437)	(2,524)
Allowance for doubtful accounts			(652)	541	(115)
Nonunion pension and other retirement plans			957	564	(2,810)
Multiemployer pension fund withdrawal			157	150	(5,818)
Federal and state net operating loss carryforwards utilized (generated)			(259)	59	746
State depreciation adjustments			343	(1,302)	(1,761)
Share-based compensation			(195)	(709)	(529)
Valuation allowance increase (decrease)			617	383	(744)
Other accrued expenses			1,663	(699)	(4,881)
Impact of the Tax Reform Act					(3,772)
Prepaid expenses			1,207	1,782	1,313
Operating lease right-of-use assets/liabilities - net			(13)	(1,049)
Other			395	(314)	(92)
Deferred tax provision			$ 7,715	$ 5,411	$ 1,872
Statutory federal rate (as a percent)	32.74%	21.00%	21.00%	21.00%	21.00%	35.00%

-- None. No documentation exists for this element. --

No definition available.

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- Definition

Represents the amount of deferred tax provision or (benefit) on allowance for doubtful accounts during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

+ References

No definition available.

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Represents the amount of deferred tax provision or (benefit) on amortization of intangible assets and impairment arising during the period due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

+ References

No definition available.

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This element represents the amount of deferred tax provision or (benefit) on equity-based compensation costs during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

+ References

No definition available.

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Represents the deferred income tax expense benefit multiemployer pension fund withdrawal.

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No definition available.

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Represents the amount of deferred tax provision or (benefit) on operating lease right-of-use assets/liabilities - net during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

+ References

No definition available.

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Represents the amount of deferred tax provision or (benefit) on federal and state operating loss carryforwards during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

+ References

No definition available.

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This element represents the amount of deferred tax provision or (benefit) on other costs not otherwise specified in the taxonomy during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

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No definition available.

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Represents the amount of deferred tax provision or (benefit) on other accrued expenses during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

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No definition available.

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This element represents the amount of deferred tax provision or (benefit) on pension and other retirement plans costs during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

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No definition available.

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Represents the amount of deferred tax provision or (benefit) on prepaid expenses during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

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No definition available.

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This element represents the amount of deferred tax provision or (benefit) on amortization, depreciation and basis difference for property, plant and equipment and other long-lived assets (excluding intangible assets) arising during the period due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

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- Definition

This element represents the amount of deferred tax provision or (benefit) on changes in reserves for workers' compensation and cargo claims arising during the period due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

+ References

No definition available.

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This element represents the amount of deferred tax provision or (benefit) on revenue recognition arising during the period due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

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No definition available.

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Represents the amount of deferred tax provision or (benefit) on state depreciation adjustments during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

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No definition available.

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This element represents the amount of deferred tax provision or (benefit) on valuation allowance during the period, due to an increase or decrease in the entity's deferred tax assets and liabilities pertaining to continuing operations.

+ References

No definition available.

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Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of income tax benefit for remeasurement of deferred tax liability from change in tax rate pursuant to Tax Cuts and Jobs Act.

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