Acquisitions - Acquired Entities (Details)						9 Months Ended
	Aug. 14, 2017	Jul. 18, 2017 USD ($) employee vehicles branches	Jun. 29, 2017	Apr. 19, 2017	Mar. 14, 2017	Sep. 30, 2017 USD ($) employee acquisition	Dec. 31, 2016 USD ($)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill						$ 407,000,000	$ 186,200,000
Maco
Business Acquisition [Line Items]
Acquisition date		Jul. 18, 2017
Percentage of shares acquired		100.00%
Potential undiscounted amount minimum		$ 0
Potential undiscounted amount maximum		$ 30,000,000				$ 30,000,000
Revenue multiple		2.5
Entity number of employees | employee		1,450
Number of branches | branches		4
Number of armored vehicles | vehicles		150
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Purchase consideration - cash paid		$ 82,800,000
Fair value of future payments to sellers		93,200,000
Contingent consideration		28,700,000
Fair value of purchase consideration		204,700,000
Cash		10,300,000
Accounts receivable		16,200,000
Other current assets		500,000
Property and equipment, net		2,400,000
Intangible assets		60,200,000
Goodwill		147,600,000
Other noncurrent assets		100,000
Current liabilities		(11,300,000)
Noncurrent liabilities		(21,300,000)
Fair value of net assets acquired		$ 204,700,000
AATI
Business Acquisition [Line Items]
Acquisition date					Mar. 14, 2017
Percentage of shares acquired					100.00%
Pag Facil
Business Acquisition [Line Items]
Acquisition date				Apr. 19, 2017
Percentage of shares acquired				100.00%
LGS
Business Acquisition [Line Items]
Acquisition date			Jun. 29, 2017
Percentage of shares acquired			100.00%
Maco Litoral
Business Acquisition [Line Items]
Acquisition date	Aug. 14, 2017
Percentage of shares acquired	100.00%
Other Acquisitions
Business Acquisition [Line Items]
Entity number of employees | employee						1,200
Number of acquired operations | acquisition						4
Goodwill increase						$ 9,000,000
Intangible assets decrease						11,000,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Purchase consideration - cash paid						77,500,000
Fair value of future payments to sellers						15,600,000
Fair value of purchase consideration						93,100,000
Cash						2,300,000
Accounts receivable						7,200,000
Property and equipment, net						8,200,000
Intangible assets						25,500,000
Goodwill						62,000,000
Other noncurrent assets						3,500,000
Current liabilities						(7,600,000)
Noncurrent liabilities						(8,000,000)
Fair value of net assets acquired						$ 93,100,000