Net Earnings Per Common Share - Calculation of Basic and Diluted Net Earnings (Loss) Per Common Share (Parenthetical) (Detail) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share Basic And Diluted [Line Items]
Additional diluted weighted average shares due to early adoption of accounting standard	[1]	196,700,000	205,800,000	197,500,000	209,500,000
Income tax provision (benefit) due to early adoption of accounting standard		$ 9.5	$ 39.4	$ 92.8	$ 88.3
Accounting Standards Update 2016-09 [Member]
Earnings Per Share Basic And Diluted [Line Items]
Additional diluted weighted average shares due to early adoption of accounting standard		377,130		370,090
Income tax provision (benefit) due to early adoption of accounting standard		$ (1.8)		$ 12.4
Earnings per common share net increase due to early adoption of accounting standard		$ 0.01		$ 0.06

[1] The Company early adopted ASU 2016-09 on a prospective basis as required, related to the recognition of excess tax benefits to the income statement which were previously recorded in additional paid-in capital, effective January 1, 2016. This resulted in an additional 377,130 and 370,090 diluted weighted average number of common shares outstanding for the three and nine months ended September 30, 2016, respectively, and recognition of excess tax benefits of $1.8 million and $12.4 million in income tax provision for the three and nine months ended September 30, 2016, respectively. As a result, net earnings per common share increased by $0.01 per share and $0.06 per share for the three and nine months ended September 30, 2016, respectively. Refer to Note 2, “Recently Issued Accounting Standards” of the notes to the condensed consolidated financial statements for further details.