RESTRUCTURING, DIVESTITURES, AND IMPAIRMENTS - Additional Information (Detail) - USD ($) $ in Millions			1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 01, 2020	Feb. 06, 2020	Aug. 31, 2020	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 01, 2021	Sep. 01, 2021
Restructuring Cost and Reserve [Line Items]
Operational optimization charges					$ 0.0	$ 3.1	$ 14.5
Impairment charges and subsequent loss on disposal					(1.7)	123.6	103.0
Gain (loss) on disposition of business					$ (1.7)	123.6	103.0
TSA period agreement					12 months
Proceeds from sale of business					$ 35.0	498.9	86.6
Impairment charges					6.7	18.3	29.4
H S A
Restructuring Cost and Reserve [Line Items]
Service agreement period		7 years
Proceeds from stock purchase agreement deferred		$ 17.7
Transmission Service Agreement
Restructuring Cost and Reserve [Line Items]
Service agreement period		6 months
Proceeds from stock purchase agreement deferred		$ 1.5
ESOL Disposal Group
Restructuring Cost and Reserve [Line Items]
Consideration for sale of business		$ 462.5
Revenue							559.6
Impairment of long-lived assets to be disposed of						53.8
Argentina
Restructuring Cost and Reserve [Line Items]
Cumulative currency translation loss realized through disposition of operations					0.0	87.2	0.0
Mexico
Restructuring Cost and Reserve [Line Items]
Cumulative currency translation loss realized through disposition of operations					0.0	0.0	18.9
Chile
Restructuring Cost and Reserve [Line Items]
Cumulative currency translation loss realized through disposition of operations					0.0	0.0	$ 16.8
Expert Solutions | Disposal group, disposed of by sale, not discontinued operations
Restructuring Cost and Reserve [Line Items]
Consideration for sale of business	$ 78.0
Revenue						75.4
TAS
Restructuring Cost and Reserve [Line Items]
Transaction services agreement period							15 months
Allocated and deferred amount							$ 5.1
TAS | North America
Restructuring Cost and Reserve [Line Items]
Consideration for sale of business							36.4
Gain (loss) on disposition of business							45.5
Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets to be disposed of					0.0	2.8	1.7
Impairment charges					6.7	8.7	16.9
Cost of sales
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets to be disposed of					0.0	0.0	5.6
Impairment charges					0.0	6.8	5.2
North America
Restructuring Cost and Reserve [Line Items]
Operational optimization charges							3.8
Impairment charges and subsequent loss on disposal					(12.6)	15.0	45.5
Impairment charges					2.1	10.3	4.5
North America | ESOL Disposal Group
Restructuring Cost and Reserve [Line Items]
Revenue							100.0
North America | Expert Solutions | Disposal group, disposed of by sale, not discontinued operations
Restructuring Cost and Reserve [Line Items]
Gain (loss) on disposition of business	(38.8)
North America | Canada Environmental Solutions Operations | Disposal group, disposed of by sale, not discontinued operations
Restructuring Cost and Reserve [Line Items]
Consideration for sale of business								$ 24.4
North America | Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets to be disposed of					0.0	0.0	0.4
Impairment charges					2.1	4.2	0.5
North America | Selling, general and administrative expenses | Customer Lists
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets to be disposed of						1.7
North America | Cost of sales
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets to be disposed of					0.0	0.0	2.0
Impairment charges					0.0	6.1	1.6
International
Restructuring Cost and Reserve [Line Items]
Operational optimization charges							10.7
Impairment charges and subsequent loss on disposal					10.9	108.6	57.5
Impairment charges					4.6	8.0	24.9
International | Argentina | Disposal group, disposed of by sale, not discontinued operations
Restructuring Cost and Reserve [Line Items]
Gain (loss) on disposition of business						112.4
Proceeds from sale of business			$ 3.9
Cumulative currency translation loss realized through disposition of operations						87.2
International | United Kingdom
Restructuring Cost and Reserve [Line Items]
Operational optimization charges						3.1
International | United Kingdom | Patient transport services
Restructuring Cost and Reserve [Line Items]
Gain (loss) on disposition of business							(0.3)
International | United Kingdom | Disposal group, disposed of by sale, not discontinued operations
Restructuring Cost and Reserve [Line Items]
Gain (loss) on disposition of business							(5.1)
Proceeds from sale of business							14.8
International | Mexico
Restructuring Cost and Reserve [Line Items]
Impairment charges and subsequent loss on disposal							43.2
Cumulative foreign currency translation adjustment							(18.9)
International | Chile
Restructuring Cost and Reserve [Line Items]
Gain (loss) on disposition of business							19.0
Proceeds from sale of business							30.7
Cumulative foreign currency translation adjustment							(16.8)
International | Romania
Restructuring Cost and Reserve [Line Items]
Impairment charges					4.6
International | Expert Solutions | Disposal group, disposed of by sale, not discontinued operations
Restructuring Cost and Reserve [Line Items]
Gain (loss) on disposition of business	$ (4.0)
International | Japan Operating Unit | Disposal group, disposed of by sale, not discontinued operations
Restructuring Cost and Reserve [Line Items]
Consideration for sale of business									$ 11.3
Gain (loss) on disposition of business				$ 10.9
Cumulative currency translation loss realized through disposition of operations				$ 3.8
International | Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets to be disposed of					0.0	2.8	1.3
Impairment charges					4.6	4.5	16.4
International | Cost of sales
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets to be disposed of					0.0	0.0	3.6
Impairment charges					$ 0.0	$ 0.7	$ 3.6