GEOGRAPHIC AREA AND SERVICES INFORMATION - Summary of Consolidated Revenues and Long-lived Assets by Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues and Long-Lived Assets [Line Items]
Revenues	$ 887.8	$ 882.8	$ 917.7	$ 892.4	$ 906.4	$ 890.1	$ 891.6	$ 874.2	$ 3,580.7	$ 3,562.3	$ 2,985.9
Long-Lived Assets	741.0				723.9				741.0	723.9	665.6
United States
Revenues and Long-Lived Assets [Line Items]
Revenues									2,716.9	2,657.4	2,165.0
Long-Lived Assets	520.8				499.1				520.8	499.1	434.2
Europe
Revenues and Long-Lived Assets [Line Items]
Revenues									436.2	486.0	441.2
Long-Lived Assets	89.8				89.0				89.8	89.0	95.8
Other International Countries
Revenues and Long-Lived Assets [Line Items]
Revenues									427.6	418.9	379.7
Long-Lived Assets	130.4				135.8				130.4	135.8	135.6
Total International
Revenues and Long-Lived Assets [Line Items]
Revenues									863.8	904.9	820.9
Long-Lived Assets	$ 220.2				$ 224.8				$ 220.2	$ 224.8	$ 231.4