Subsequent Event - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended	9 Months Ended	0 Months Ended
	Oct. 28, 2013	Sep. 30, 2014	Oct. 27, 2014 Subsequent Event
Subsequent Event [Line Items]
Special cash dividend declared, date		Oct. 28, 2013	Oct. 27, 2014
Special cash dividend record, date		Nov. 08, 2013	Nov. 07, 2014
Special cash dividend declared per share	$ 0.35		$ 0.50
Special cash dividend paid	$ 23.0		$ 33.0
Special cash dividend paid, date		Jan. 02, 2014	Nov. 20, 2014