Goodwill and Other Intangible Assets - Schedule of Key Assumptions Used in Deriving Reporting Units Fair Value (Detail)	Sep. 30, 2019
Discount rate [Member] | NCSA [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.330
Discount rate [Member] | EARC [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.335
Discount rate [Member] | MENA [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.340
Discount rate [Member] | Technology [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.150
Compound annual growth rate [Member] | NCSA [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.29
Compound annual growth rate [Member] | EARC [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.46
Compound annual growth rate [Member] | MENA [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.17
Compound annual growth rate [Member] | Technology [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.08
Terminal growth rate [Member] | NCSA [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.02
Terminal growth rate [Member] | EARC [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.02
Terminal growth rate [Member] | MENA [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.02
Terminal growth rate [Member] | Technology [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill Measurement Input	0.02