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Auction Rate Securities - Significant Assumptions Used to Determine Fair Value of Auction Rate Securities (Detail)
 3 Months Ended 12 Months Ended
Jan. 31, 2015
Oct. 31, 2014
Schedule of Available-for-sale Securities    
Libor plus stated yield 2.00%abm_SecuritiesYieldsOverLondonInterbankOfferedRate 2.00%abm_SecuritiesYieldsOverLondonInterbankOfferedRate
Yields 2.15%abm_SecuritiesYields 2.15%abm_SecuritiesYields
Minimum    
Schedule of Available-for-sale Securities    
Discount rates 0.30%abm_SecuritiesDiscountRateOverLondonInterbankOfferedRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		 0.28%abm_SecuritiesDiscountRateOverLondonInterbankOfferedRate
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Average expected lives 4 years 4 years
Maximum    
Schedule of Available-for-sale Securities    
Discount rates 5.03%abm_SecuritiesDiscountRateOverLondonInterbankOfferedRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		 4.06%abm_SecuritiesDiscountRateOverLondonInterbankOfferedRate
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Average expected lives 10 years 10 years