Income Taxes - Components of Earnings Before Income Taxes and Provision for Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
United States									$ 345.6	$ 288.1	$ 245.1
Foreign, principally Australia, Canada, New Zealand and the U.K.									(52.1)	3.4	45.9
Earnings before income taxes	$ 28.4	$ 105.7	$ 128.5	$ 30.9	$ 30.3	$ 95.4	$ 111.9	$ 53.9	293.5	291.5	291.0
Federal Current									43.9	38.8	29.0
Federal Deferred									(139.4)	(96.6)	(47.7)
Total Provision (benefit) for income taxes, Federal									(95.5)	(57.8)	(18.7)
State and local Current									18.9	19.5	10.6
State and local Deferred									(3.3)	(1.1)	(0.6)
Total Provision (benefit) for income taxes, State and local									15.6	18.4	10.0
Foreign Current									22.9	30.5	29.0
Foreign Deferred									(38.6)	(27.1)	(13.9)
Total Provision (benefit) for income taxes, Foreign									(15.7)	3.4	15.1
Provision (benefit) for income taxes									$ (95.6)	$ (36.0)	$ 6.4