Goodwill and Intangible Assets - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Goodwill and Intangible Assets Disclosure [Line Items]
Amortization expense on identifiable intangible assets	$ 10.6	$ 7.4	$ 19.7	$ 15.1
Expected amortization expenses in year one	50		50
Expected amortization expenses in year two	50		50
Expected amortization expenses in year three	50		50
Expected amortization expenses in year four	50		50
Expected amortization expenses in year five	50		50
Goodwill increase during period			$ 726