Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Components of Benefit for Income Taxes

The components of the (benefit) expense from income taxes are comprised of the following for the years ended December 31:

	2019			2018			2017
Current
Federal	$	(6.4	)	$	(3.2	)	$	(1.1	)
State	(12.6		)	3.2			1.2
	(19.0		)	—			0.1
Deferred
Federal	(5.8		)	6.2			(44.8		)
State	4.4			(1.6		)	3.5
	(1.4		)	4.6			(41.3		)
(Benefit) expense from income taxes	$	(20.4	)	$	4.6		$	(41.2	)

Reconciliation between Benefit for Income Taxes and Expected Tax Provision

A reconciliation between the benefit or expense from income taxes and the expected tax benefit or expense using the federal statutory rate in effect for the years ended December 31 is as follows: 

	2019			2018			2017
Amount computed using statutory rates	$	(5.7	)	$	3.0		$	(1.0	)
State income taxes, net of federal benefit	(4.1		)	(1.8		)	(3.3		)
Benefit from stock option exercises	(2.4		)	—			—
Acquisition related costs	1.9			—			—
Net effect of changes in tax rates	—			—			(0.3		)
Uncertain tax positions and interest	(28.1		)	0.5			0.5
Nondeductible expenses	1.6			0.5			1.5
Net effect of change in U.S. Tax Law	—			—			(40.4		)
Other	0.2			0.2			0.6
Valuation allowance	16.2			2.2			1.2
(Benefit) expense from income taxes	$	(20.4	)	$	4.6		$	(41.2	)

Summary of Company's Deferred Tax Assets and Liabilities

The Company’s deferred tax assets and liabilities relate to the following sources and differences between financial accounting and the tax basis of the Company’s assets and liabilities at December 31:

	2019			2018
Deferred tax assets
Allowance for doubtful accounts	$	1.2		$	1.2
Insurance reserve	12.9			12.5
Net operating loss	115.5			100.7
Accrued bonus and vacation	4.7			4.1
Stock compensation	5.2			6.0
Tax credits	1.9			1.7
Other	9.9			12.0
Total deferred tax assets	151.3			138.2
Valuation allowance	(23.0		)	(15.4		)
Deferred tax assets less valuation allowance	128.3			122.8
Deferred tax liabilities
Fixed asset basis	(101.2		)	(82.9		)
Intangible basis	(69.9		)	(70.9		)
Landfill and environmental remediation liabilities	(41.1		)	(52.3		)
Other	(4.6		)	(7.8		)
Deferred tax liabilities	(216.8		)	(213.9		)
Net deferred tax liability	$	(88.5	)	$	(91.1	)

Reconciliation of Beginning and Ending Amount of Gross Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of gross unrecognized tax benefits for fiscal 2019, 2018 and 2017 is as follows:     

	2019			2018		2017
Balance at January 1,	$	27.6		$	27.5	$	7.5
Additions based on tax positions of prior years	—			—		20.4
Change to prior tax positions due to tax rate changes	—			—		(0.4		)
Additions based on tax positions of current year	—			0.1		—
Reduction due to settlements with tax authorities	(27.6		)	—		—
Balance at December 31,	$	—		$	27.6	$	27.5