Goodwill and Other Intangibles - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization expense related to other intangible assets	$ 10.9	$ 19.5	$ 21.1
Estimated future amortization expense for 2016	8.4
Estimated future amortization expense for 2017	8.4
Estimated future amortization expense for 2018	7.7
Estimated future amortization expense for 2019	7.5
Estimated future amortization expense for 2020	$ 7.5