Income Taxes - Summary of Tax Years that Remain Subject to Examination by Major Jurisdiction (Detail)	12 Months Ended
	Dec. 31, 2017
United States - Federal [Member] | Minimum [Member] | United States [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2014
United States - Federal [Member] | Maximum [Member] | United States [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2016
State and Local Jurisdiction [Member] | Minimum [Member] | United States [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2012
Examination in progress	2013
State and Local Jurisdiction [Member] | Maximum [Member] | United States [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2016
Examination in progress	2014
Foreign Tax Authority [Member] | Canada [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2016
Foreign Tax Authority [Member] | Germany [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2016
Foreign Tax Authority [Member] | Minimum [Member] | Canada [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2010
Examination in progress	2014
Foreign Tax Authority [Member] | Minimum [Member] | Germany [Member]
Income Tax Examination [Line Items]
Examination in progress	2012
Foreign Tax Authority [Member] | Minimum [Member] | France [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2014
Examination in progress	2011
Foreign Tax Authority [Member] | Minimum [Member] | United Kingdom [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2015
Foreign Tax Authority [Member] | Minimum [Member] | Philippines [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2015
Foreign Tax Authority [Member] | Maximum [Member] | Canada [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2013
Examination in progress	2015
Foreign Tax Authority [Member] | Maximum [Member] | Germany [Member]
Income Tax Examination [Line Items]
Examination in progress	2015
Foreign Tax Authority [Member] | Maximum [Member] | France [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2016
Examination in progress	2012
Foreign Tax Authority [Member] | Maximum [Member] | United Kingdom [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2016
Foreign Tax Authority [Member] | Maximum [Member] | Philippines [Member]
Income Tax Examination [Line Items]
Examinations not yet initiated	2016