Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill impairment	$ 1.9		$ 1.9	$ 0.4
Amortization expense		0.1	0.1	0.1
Expected amortization expense, 2014		0.1
Expected amortization expense, 2015		0.1
Expected amortization expense, 2016		0.1
Expected amortization expense, 2017		0.1
Expected amortization expense, 2018		0.1
Expected amortization expense, thereafter		$ 0.2