Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0000771497 (http://www.sec.gov/CIK)

Income Tax Disclosure [Abstract]	Period [Axis]
	2015-11-01 - 2016-10-31
Income Tax Disclosure [Abstract]
Geographic Sources of Income Before Income Taxes	Geographic Sources of Income Before Income Taxes   Years Ended October 31, (in millions) 2016   2015   2014 United States $ 45.1   $ 60.5   $ 104.5 Foreign 6.8   11.9   6.1 Income before income taxes $ 51.9   $ 72.4   $ 110.6
Components of Income Tax Provision	Components of Income Tax Benefit (Provision)   Years Ended October 31, (in millions) 2016   2015   2014 Current:           Federal $ 17.5   $ (3.7 )   $ (32.6 ) State (9.3 )   (3.7 )   (7.6 ) Foreign (1.5 )   (2.8 )   (1.3 ) Deferred:           Federal 3.6   (7.9 )   (0.8 ) State (0.5 )   (0.3 )   (1.4 ) Foreign 0.6   0.1   — Income tax benefit (provision) $ 10.4   $ (18.3 )   $ (43.7 )
Reconciliation of US Statutory Tax Rate to Annual Effective Tax Rate	Reconciliation of the U.S. Statutory Tax Rate to Annual Effective (Benefit) Tax Rate   Years Ended October 31,   2016   2015   2014 U.S. statutory rate 35.0  %   35.0  %   35.0  % State and local income taxes, net of federal tax benefit 7.8   6.5   6.7 Federal and state tax credits (22.7 )   (9.6 )   (2.2 ) Impact of foreign operations (5.0 )   (3.6 )   (1.1 ) Changes in uncertain tax positions (40.0 )   (5.2 )   (2.0 ) Incremental tax benefit from share-based compensation awards (4.2 )   —   — Nondeductible expenses 7.7   3.8   2.6 Other, net 1.4   (1.6 )   0.5 Annual effective (benefit) tax rate (20.0 )%   25.3  %   39.5  %
Components of Deferred Tax Assets and Liabilities	Components of Deferred Tax Assets and Liabilities   As of October 31, (in millions) 2016   2015 Deferred tax assets attributable to:       Self-insurance claims (net of recoverables) $ 108.4   $ 109.5 Deferred and other compensation 33.4   35.5 Impairment loss on assets held for sale 9.2   — Accounts receivable allowances 6.6   2.9 Settlement liabilities 2.6   3.5 Other accruals 2.9   2.6 Other comprehensive income 1.5   1.3 State taxes 0.6   0.5 State net operating loss carryforwards 5.7   5.9 Tax credits 9.9   7.4 Other 2.5   0.4 Gross deferred tax assets 183.3   169.5 Valuation allowance (5.4 )   (5.5 ) Total deferred tax assets 177.9   164.0         Deferred tax liabilities attributable to:       Property, plant and equipment (2.2 )   (0.4 ) Goodwill and other acquired intangibles (141.8 )   (129.5 ) Total deferred tax liabilities (144.0 )   (129.9 )         Net deferred tax assets $ 33.9   $ 34.1
Valuation Allowance Rollforward	Changes to the Deferred Tax Asset Valuation Allowance   Years Ended October 31, (in millions) 2016   2015   2014 Valuation allowance at beginning of year $ 5.5   $ 6.2   $ 6.2 Sale of Security business —   (0.8 )   — Other, net (0.1 )   0.1   — Valuation allowance at end of year $ 5.4   $ 5.5   $ 6.2
Reconciliation of Total Unrecognized Tax Benefits	Reconciliation of Total Unrecognized Tax Benefits   Years Ended October 31, (in millions) 2016   2015   2014 Balance at beginning of year $ 82.5   $ 85.5   $ 87.6 Additions for tax positions related to the current year —   2.1   1.4 Reductions for tax positions related to the current year —   —   — Additions for tax positions related to prior years —   0.1   — Reductions for tax positions related to prior years (3.2 )   —   — Reductions for lapse of statute of limitations (21.9 )   (5.2 )   (3.2 ) Settlements (0.2 )   —   (0.3 ) Balance at end of year $ 57.2   $ 82.5   $ 85.5
Summary of Income Tax Examinations	Tax Years Open for Examination, by Entity Entity Open by Statute ABM state tax returns(1) 10/31/2012 – 10/31/2016 ABM federal tax returns 10/31/2013 – 10/31/2016 (1) We are currently being examined by the taxing authorities in the states of Alabama, Arizona, Connecticut, New Jersey, North Carolina, and Tennessee.