Net Earnings Per Common Share - Calculation of Basic and Diluted Net Earnings (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
Numerator
Net earnings available to common stockholders	$ 49.6	$ 28.1	[1]	$ 141.5	$ 125.3	[1],[2]
Distributed and allocated undistributed net loss to non-vested restricted stockholders	(0.4)	(0.3)		(1.0)	(0.9)
Distributed and allocated undistributed net earnings to common stockholders	49.2	27.8		140.5	124.4
Distributed net earnings - dividends paid to common stockholders	(31.3)	(27.2)		(56.7)	(54.5)
Allocation of undistributed net earnings to common stockholders	$ 17.9	$ 0.6		$ 83.8	$ 69.9
Denominator
Weighted average number of common shares outstanding - basic	195.6	208.5		195.4	208.7
Basic net earnings per common share:
Distributed net earnings to common stockholders	$ 0.16	$ 0.13		$ 0.29	$ 0.26
Allocated undistributed net earnings to common stockholders	0.09			0.43	0.34
Basic net earnings per common share:	$ 0.25	$ 0.13		$ 0.72	$ 0.60
Numerator
Distributed and allocated undistributed net earnings to common stockholders	$ 49.2	$ 27.8		$ 140.5	$ 124.4
Add: Allocated undistributed net earnings to unvested restricted stockholders	0.2			0.6	0.5
Less: Undistributed net earnings (loss) reallocated to non-vested restricted stockholders	(0.2)			(0.6)	(0.5)
Net earnings available to common stockholders - diluted	$ 49.2	$ 27.8		$ 140.5	$ 124.4
Denominator
Weighted average number of common shares outstanding - basic	195.6	208.5		195.4	208.7
Effect of contingently issuable shares	0.8	1.3		0.6	1.3
Effect of unvested restricted stock units	0.8	0.7		0.8	0.7
Weighted average number of common shares outstanding - diluted under two-class	197.2	210.5		196.8	210.7
Effect of unvested restricted stock - participating security	0.7	0.8		0.7	0.8
Weighted average number of common shares outstanding - diluted under treasury stock	197.9	211.3		197.5	211.5
Diluted net earnings per common share	$ 0.25	$ 0.13		$ 0.71	$ 0.59

[1] For the three and six months ended June 30, 2015, certain foreign currency translation adjustments were misclassified on the Condensed Consolidated Statement of Comprehensive Income in deferred pension items and unrealized losses on cash flow hedge derivative instruments. See Note 1 “Organization and Basis of Presentation” under the heading “Reclassifications and Revisions” for further discussion of the revisions.

[2] For the six months ended June 30, 2015, certain amounts related to the settlement of a net investment hedge and foreign currency gains and losses were misclassified. Additional revisions were made to the Condensed Consolidated Balance Sheet as of June 30, 2015. As a result, corresponding changes were made on the Condensed Consolidated Statement of Cash Flows. See Note 1 “Organization and Basis of Presentation” under the heading “Reclassifications and Revisions” for further discussion of the revisions.