Commitments and contingencies - Loss Contingencies (Detail)	9 Months Ended
	Sep. 30, 2014
Grable [Member]
Loss Contingencies [Line Items]
Plaintiff	Grable
Month Served	Aug-08
Jurisdiction	6th Judicial Circuit Court, Pinellas County, FL
Claim Type	Training Injury
Status	Discovery Phase
Koon [Member]
Loss Contingencies [Line Items]
Plaintiff	Koon
Month Served	Dec-08
Jurisdiction	17th Judicial Circuit Court, Broward County, FL
Claim Type	Training Injury
Status	Discovery Phase
Derbyshire [Member]
Loss Contingencies [Line Items]
Plaintiff	Derbyshire
Month Served	Nov-09
Jurisdiction	Ontario, Canada Superior Court of Justice
Claim Type	Officer Injury
Status	Discovery Phase
Thompson [Member]
Loss Contingencies [Line Items]
Plaintiff	Thompson
Month Served	Mar-10
Jurisdiction	11th Judicial Circuit Court, Miami-Dade County, FL
Claim Type	Suspect Injury During Arrest
Status	Discovery Phase
Doan [Member]
Loss Contingencies [Line Items]
Plaintiff	Doan
Month Served	Apr-10
Jurisdiction	The Queens Bench Alberta, Red Deer Judicial Dist.
Claim Type	Wrongful Death
Status	Discovery Phase
Shymko [Member]
Loss Contingencies [Line Items]
Plaintiff	Shymko
Month Served	Dec-10
Jurisdiction	The Queens Bench, Winnipeg Centre, Manitoba
Claim Type	Wrongful Death
Status	Pleading Phase
Juran [Member]
Loss Contingencies [Line Items]
Plaintiff	Juran
Month Served	Dec-10
Jurisdiction	Hennepin County District Court, 4th Judicial District
Claim Type	Officer Injury
Status	Pleading Phase
Wilson [Member]
Loss Contingencies [Line Items]
Plaintiff	Wilson
Month Served	May-11
Jurisdiction	US District Court, ED MO
Claim Type	Wrongful Death
Status	Trial scheduled for Nov. 2014
Ramsey [Member]
Loss Contingencies [Line Items]
Plaintiff	Ramsey
Month Served	Jan-12
Jurisdiction	17th Judicial Circuit Court, Broward County, FL
Claim Type	Wrongful Death
Status	Discovery Phase
Firman [Member]
Loss Contingencies [Line Items]
Plaintiff	Firman
Month Served	Apr-12
Jurisdiction	Ontario, Canada Superior Court of Justice
Claim Type	Wrongful Death
Status	Pleading Phase
Ricks [Member]
Loss Contingencies [Line Items]
Plaintiff	Ricks
Month Served	May-12
Jurisdiction	US District Court, WD LA
Claim Type	Wrongful Death
Status	Motion Phase
Miller [Member]
Loss Contingencies [Line Items]
Plaintiff	Miller
Month Served	Jan-13
Jurisdiction	New Castle County Superior Court, DE
Claim Type	Wrongful Death
Status	Discovery Phase
Rascom [Member]
Loss Contingencies [Line Items]
Plaintiff	Rascom
Month Served	Apr-14
Jurisdiction	US District Court, AZ
Claim Type	Wrongful Death
Status	Pleading Phase
Schrock [Member]
Loss Contingencies [Line Items]
Plaintiff	Schrock
Month Served	Sep-14
Jurisdiction	San Bernardino County Superior Court, CA
Claim Type	Wrongful Death
Status	Pleading Phase
Ward [Member]
Loss Contingencies [Line Items]
Plaintiff	Ward
Month Served	Oct-14
Jurisdiction	Richmond County Superior Court, GA
Claim Type	Officer Fired
Status	Pleading Phase
Moore [Member]
Loss Contingencies [Line Items]
Plaintiff	Moore
Month Served	Oct-14
Jurisdiction	St. Louis County Circuit Court, MO
Claim Type	Wrongful Death
Status	Pleading Phase